Kouki Amanogawa/Relationships

Seiji Amanogawa
Kouki's father. Kouki inherited his physical appearance from him. Kouki loves his father very much.

As stated by their history, Seiji cares deeply for his son and is aware of his childish ideals due to his grandfather's influence, and like his wife, attempted numerous times to properly educate his son on the fact that how the world worked was not simply black and white and that it was more complicated than he thinks. Kouki, unwilling and never really going through any actual hardships he couldn't overcome prior to being summoned to Tortus, mostly brushed off his father's attempts and ignored him.

Miya Amanogawa
Kouki's mother. Kouki inherited his wanderlust and trouble-making habits from her. It is due to her worrying that Kouki might inherit her trouble making nature that she made him enroll as a student of the Yaegashi Dojo. Kouki loves his mother very much.

As stated by their history, Like her husband, Miya care deeply for her son and is aware of his childish ideals and like her husband, attempted numerous times to educate and correct him and attempted to teach him that the world was more complicated than he thinks and of how everything wasn't just black and white. Kouki, due to having never come across any actual hardships that he couldn't overcome prior to being summoned to Tortus, mostly brushed off and ignored his mother's attempts.

Mitsuki Amanogawa
Mistuki is Kouki's younger spoiled bratty sister and the head of the Soul Sisters. Mitsuki is disappointed at her brother for not able to make Shizuku his wife thus resulting in Mitsuki calling Kouki an idiot. This is due to Shizuku loving Hajime Nagumo and rejecting Kouki for his misguided justice which almost broke his relationship with Shizuku. Kouki doesn't know about his sister's darker nature due to her hiding it from him and Shizuku.

Hajime Nagumo
Prior to the summoning, Kouki disliked Hajime and considered him to be a bother, viewing the latter as constantly fawning over Kaori due to his convenient misinterpretation of her attitude towards him. Kouki was so ignorant about Hajime that he stupidly believed his classmate was nothing but a lazy otaku that doesn't study or do sports. He also thinks Hajime smiles like an idiot.

Likewise, Hajime also hates Kouki for the most part as he views the former to be an annoyingly immature idiot with grand words lost in his own delusions that he wants to avoid dealing with due to his naive mindset and troublesome habit of interpreting everything to fit his worldview, especially after his trials in the Great Orcus Labyrinth. It is due to these flaws that Hajime decided not to reveal to Kouki and his classmates that the god, Ehit, who had summoned them to be heroes in Tortus, was in fact a twisted evil god that viewed living beings as playthings or the fact that Daisuke Hiyama attempted to kill Hajime himself, since Kouki's idiotic idealistic mindset would never allow him to doubt those who are praising him. Hajime doesn't take orders from Kouki and ignored every single one of his commands that he tried to give him. Hajime absolutely refused to let Kouki take his lovers even through pointless and childish challenges during which Hajime easily defeated him twice: first in an unarmed duel when he dropped Kouki in a pitfull with non-lethal grenades and later fighting while the latter was merged with his Schnee doppelganger.

During their reunion in the Great Orcus Labyrinth, upon seeing Hajime's newfound immense power as well as being dearly loved and adored by the extremely beautiful Yue, Shea, and Tio, in addition to Kaori, who eventually decided to follow Hajime, Kouki became extremely jealous of him and started one-sidedly seeing Hajime as his rival. This is also coupled with the fact that both of them have completely opposite ways of thinking, as Kouki is a naive idealist obsessed with justice while Hajime is a disillusioned realist whose only concern is surviving and returning home with his harem. When Hajime disregarded his pleas and ruthlessly killed Cattleya even though she could no longer fight anymore, Kouki foolishly believed Hajime was just an uncaring murderer who doesn't treat his harem "nicely" despite the demon's previous attempt to kill him, his party, and the Heiligh knights. He also stupidly saw Hajime's cold refusal to rejoin them in the war against the demons, despite possessing extremely powerful firearms and artifacts, as a sign of utter selfishness without even trying to know the reason behind his refusal. Kouki also furiously questioned why Hajime is the only one who has a harem with him while he himself doesn't have one. However, Shizuku correctly countered Kouki's delusional thinking by telling him that he doesn't truly know a single thing about Hajime, even before their summoning to Tortus, such as the latter's kindhearted nature and also that despite his tremendous change in personality and attitude, Hajime still retained his kindness, which earned him the love and affections of not only Kaori but also Yue, Shea and Tio who are always happy around Hajime. Shizuku also told Kouki that he is the only one who was ignoring reality by interpreting the situation to his own convenience just to convince himself that Hajime is a demon who doesn't deserve Kaori.

Unlike his other classmates who were praised and respected by Hajime for succeeding in conquering the Great Labyrinths after resolving themselves to defeat Ehit in order to return home, Kouki is the only one who was completely sidelined due to his lack of resolve that led to his failures as well as when he was continually trying to enforce his delusional belief of justice on Hajime and his harem. Kouki was the only one who condemned Hajime for murdering Hiyama despite the latter's atrocities and betrayal including temporarily murdering one of his best friend Kaori. Despite the fact that Hajime revived Kaori, Kouki doesn't expressed his gratitude at all due to his naive sense of justice, childish ideals and delusional pride unlike Ryutarou and Shizuku.

At first, upon their reunion, Kouki persistently believed he could still defeat Hajime, at least in terms of hand-to-hand combat, despite having seen the latter easily defeated Cattleya and her monster army that nearly killed both Kouki himself and his party, even foolishly challenged Hajime to his failed attempted take Hajime's lovers by force. It was only during the demon invasion of the Heiligh Kingdom's capital that Kouki didn't dare to go against Hajime due to having witnessed his true power when he both easily destroyed all the undead Heiligh knights including the former captain, Meld Loggins, who were the finest warriors of the Heiligh Kingdom and single-handedly destroyed the invading demon army of 100,000 with his Hyperion satellite weapon. When Hajime effortlessly and ruthlessly brutalized Daisuke Hiyama, who was thought to be one of the strongest among Kouki's fellow heroes, with his bare hands before throwing the latter to a horde of monsters for them to devour him, Kouki also finally understood not only Hajime's superiority to himself in physical prowess alone but also the terrifying extent of Hajime's savage brutality towards enemies and his previous claim of not showing any mercy even towards his own classmates.

Despite having been saved twice by Hajime during Cattleya's ambush and Freid Bagwa's invasion, rather than being grateful, Kouki became even more jealous of him. Following the demons' retreat from the kingdom and Aiko and Princess Liliana exposing Ehit's true evil nature, Kouki angrily blamed Hajime for indirectly causing the deaths of Meld, Kondou and the other Heiligh knights along with the near-destruction of the Heiligh Kingdom by not telling him about Ehit's tyranny earlier towards the Tortus inhabitants by manipulating them through religious worships and the evil god's schemes in using them as pawns such as sending Noint to assist Hiyama and Eri in betraying the "Hero Party" by brainwashing and later assassinating King Eliheid and his nobles, nearly leading to their deaths in Eri's death trap and also Kaori's temporary murder who nearly became Hiyama's undead slave. In response, Hajime simply told Kouki that even if he did decide to bother telling him about Ehit's true nature as an evil god, Kouki's idiotic naivety and delusional self-righteousness would just lead him to disregard Hajime's warning anyway by elaborately pointing out his habit of interpreting everything to his own convenience and his delusional pride in his efforts as Ehit's so called chosen hero, even correctly stating that just like the Holy Church and the Heiligh Kingdom, Kouki will even get mad at Hajime for supposedly slandering Ehit instead of listening to his warning. Unable to deny this claim, due to Kouki being fully aware of his complete confidence in his misguided justice, which he would angrily deny Hajime's warning instead of heeding it, Kouki still stubbornly claimed that Hajime could have convinced him otherwise by thoroughly explaining it several times. This, however, caused an annoyed Hajime to sharply insult Kouki, scolding the latter for naively believing that his classmates are always obliged to help each other which wasn't truly the case as Hajime himself had no reason to specially put in any extra effort just to suit the convenience of his delusional justice like Shizuku and Ryutarou did. Hajime then coldly reminded Kouki of the fact that it is precisely his own naive belief that classmates are always obliged to help and protect each other that was the very weakness that allowed Eri Nakamura and Daisuke Hiyama to manipulate and then betray him without even noticing it until it was too late.

Though Kouki had finally been placed before the undeniable reality at how his naive idealism had only let those under his command to betray the party, he still condemned Hajime for what happened. Kouki's stubbornness however is mostly due to the fact that he was simply unable to accept his own failures and the reality of his position in Tortus as a mere pawn of the evil god's mad game of death instead of being the so-called "chosen hero" of Tortus which Kouki had always been proud of, causing Hajime to simply dismiss both Kouki and his opinions even more. Kouki was further upset that despite his immense power, Hajime didn't believe he need to use his power for "justice" by saving Tortus from Ehit's tyrannical manipulation because that's not what he wants, as the reason why Hajime risked his life attaining the Age of God's Magic in the Great Labyrinths was simply to return home with his harem. When Kouki berated Hajime for his refusal to use his newfound powers and the Ancient Magic he attained to save Tortus, Hajime critcized Kouki's lack of resolve which is what led to his failures despite having been blessed by Ehit as the strongest of their class at the beginning. He also warned Kouki that if he kept continuing to try enforcing his stupid justice upon him, it will be his turn to die a miserable death similar to Hiyama, a warning Kouki begrudgingly heeded this time due to not having the power and courage to go against Hajime after personally witnessing how his former classmate brutally killed Hiyama for crossing him.

Despite being greatly annoyed by Kouki's stubborn delusional idealism which made him want to kill the latter out of the sheer annoyance of it, Hajime reluctantly agreed to Kouki's demand to allow his former classmates to join him in conquering the last two Great Labyrinths due to the sincere pleas of Shizuku, Suzu, and Ryutarou. Despite this, Kouki still held immense resentment and frustration towards Hajime out of the belief that Hajime is a selfish and uncaring murderer due to his cold refusal to save the people of Tortus from Ehit's malicious manipulations despite having become extremely powerful after surviving and conquering the Orcus Dungeon, which contradicts his ideals, along with his tremendous jealousy of Hajime being absolutely adored by Yue, Shea, Tio, Kaori and later also Shizuku.

After Kouki and his party joined Hajime's party in their journey to conquer the remaining Great Labyrinths, Kouki's idealistic worldview and his desire to save everyone clashed with Hajime's more realistic worldview and his desire to return home above all else. It was in the Hoelscher Empire that Hajime nearly lost his patience with Kouki, angrily warning the "hero" that he doesn't care about his misguided justice and unlike Shizuku, Kaori and Ryutarou, they are not friends nor comrades and certainly do not believe in the same ideology of justice. He also outright told Kouki that since he had left the latter's party after his fall into the abyss in the Great Orcus Labyrinth, coupled with reveal of Ehit's true nature, he is no longer obliged to obey him as Ehit's so called 'chosen hero', threateningly reminding Kouki of his original purpose in accompanying him to conquer the last remaining two Great Labyrinths and that Hajime can reject at anytime if Kouki dares to anger him again, even if he had to break both Kouki's arms and legs and send him back to the kingdom just like he broke Hiyama.

Kouki also tends to try interfering in situations where it seems that Hajime is at first reluctant to act and tends to disapprove of Hajime's more ambiguous actions, such as helping the Haulia Tribe defeat the empire, even when their aim was to liberate the enslaved beastmen that Kouki himself had wanted to help. While Kouki was initially confident that he could easily clear a Great Labyrinth and quickly become as strong as Hajime, he discovers how wide the distance between their strength is. After his personal failure in conquering the Haltina Labyrinth, Kouki gave his equipment to Hajime, in order to have a better chance to successfully conquer the last Great Labyrinth. Despite this, Kouki is reluctant to accept help from Hajime so much so that he initially refuses to use the new abilities of his Holy Sword that Hajime added due to the fact that he wants to prove he is stronger then Hajime in order to validate his righteousness. Though his attempts at this endeavor has only made things worse for himself when he failed to clear even a single one of the Great Labyrinth's and Hajime had cleared them all with ease meaning that he lost to his former classmate in both willpower and strength.

Due to Hajime's new appearance and atmosphere as well as being surrounded by a harem of beautiful girls which even included his childhood friend Kaori (who has been in love with Hajime since she first saw him), Kouki became jealous of his ability to attract the love of beautiful girls and Shizuku (who also later fell in love with Hajime) claimed that Hajime has become more popular than Kouki as he's losing his popularity for girls which eventually proved to be true.

Kouki eventually snapped when he saw Shizuku with Hajime together and finally noticing her growing feelings for him. During the final trial in the Frost Caverns of Schnee, he was forced to confront his worst personality traits in the form of a magic doppelgänger, who encouraged these self-satisfactory delusions and taunted him further in his failures, shortcomings and his inability to see reality for what it truly is.

This eventually caused him to lash out instead of accepting and conquering these negative aspects of himself and acknowledging them, choosing to believe that Hajime was only a monster who "brainwashed" not only Shizuku, but all his other lovers to get what he wanted in order to better fit into his delusional worldview. Thus, he tried to kill Hajime to fulfill his misguided justice and claim Hajime's harem for himself by forcing them to join him in continuing his previously pointless heroic crusade in order to restore his personal pride and glory as the chosen hero of Ehit whom he had absolute faith in before Hajime exposed Ehit's true nature as an evil god. Kouki also furiously blamed Hajime for his own failures and errors, indignantly questioning why his harem, including Kouki's childhood friends Kaori and Shizuku, dearly love him and became so loyal to him even though he is an uncaring murderer who disregards justice and morality. Delusionally believing himself to still be Ehit's chosen hero, Kouki brazenly declared that he will save Hajime's harem from his "brainwashing" and reclaim his self-proclaimed rightful place as their ideal lover whom they were supposed to be with instead of Hajime, claiming Yue, Shea, Tio, Kaori and Shizuku doesn't need Hajime anymore which caused Hajime to be enraged further due to his love for his harem and made him lost all of his patience with Kouki, thereby making Kouki suffer for his insolence.

When Hajime finally reached the end of his patience with Kouki's delusional justice, he did not hesitate to retaliate back with brutal force when he easily overpowered Kouki, having no qualms in shooting Kouki's kneecaps and also ruthlessly thrashing him so without any difficulty, despite Kouki's fusion with his döppelganger, which wasn't enough to match Hajime, and while the latter sharply criticized that the reason why he ended up failing everything he did in Tortus up to his own döppelganger trial in the Great Labyrinth of Schnee is because of his own choice to prioritize both his foolish pride and stubborn adherence to his childish misguided justice over the importance of realizing his own goals. When Kouki said Yue's name without honorifics, Hajime made Kouki suffer for the worse due to him having no rights to say the name that he had given to his lover. Despite wanting to kill Kouki out of his ruthless pragmatism, Hajime ultimately chose to not to because it would have made Kaori and Shizuku sad.

Instead, Hajime used Grentzen to separate Kouki's fusion with his Schnee doppelgänger and render him unconscious to end yet another pointless fight, then as the "hero" weakly begged Hajime to give him back what's rightfully his and die, the latter easily defeated Kouki yet again before allowing Kaori to heal Kouki, albeit only to a point where his life is not in danger. This is because Hajime knew that if Kouki were to immediately regain consciousness and learn of his failure in overcoming his Schnee trial, thereby his second attempt to gain the Age of God's Magic, he would simply vent his increased frustration by attacking Hajime again. After waking up and calming down, Kouki felt bad about how he attacked Hajime.

While Hajime and Yue were creating the Crystal Key to bring them back to Japan, Kouki and the others experienced what Hajime went through when he fell into the abyss of the Great Orcus Labyrinth. Witnessing the pain, suffering and loneliness Hajime experienced and his determination to return home, Kouki finally realized where Hajime's immense power came from as well as why the latter had abandoned his morality along with why he couldn't match Hajime; the difference in their circumstances and resolves to accomplish their goals. This is reflected on the fact that Kouki had heavily relied on both Ehit's blessings as his "chosen hero" and the support of the Hero Party, the Holy Church, and the Heiligh Kingdom in his previous heroic crusade while Hajime, without any of Ehit's blessings or anyone's support, had been forced to survive the horrifying brutality of the Great Orcus Dungeon alone through sheer willpower, which Kouki could never do. Additionally, Hajime had resolved to abandon all his virtues and morality to be able to survive the chaotic brutality of the war-engulfed Tortus while Kouki stubbornly prioritized his ideals over everything. After seeing Hajime's memories of his fall into the abyss, Kouki was also finally able to sympathize with Hajime's desire to return home, but he still stubbornly insist that Hajime has stolen everything from him, the love of Kaori and Shizukj and his glory as a hero and thinks that he is not mistaken in this belief.

In the After Story however, Kouki has trouble sorting out his feelings towards Hajime as due to his past actions and failures, Kouki cannot bring himself to be angry at Hajime but rather disappointed at himself for being so completely indecisive and not strong enough to realize his ideals. When the "Dark Beings" attacked, he thought about asking Hajime to transport the "Dark Beings" to another world, so that the people of Synclea Kingdom could be safe and the "Dark Beings" could survive without harming others. He was reminded of Hajime's way of prioritizing those close to him when he heard Koone's wish to save her sister above all. When Kouki was about to escape from Arquette that was attacked by the Dark "Beings", he thought how he wanted to meet Hajime again along with his family and friends.

After defeating the "Dark Beings" that were attacking Arquette, Kouki resolved himself to fight for the sake of what he believed while accepting everything in contrast to Hajime's view of dividing the world between enemy and ally. Kouki and Hajime finally reunited when Kouki was about to be attacked by a pack of "Dark Beings", as Hajime dispatched them. Hajime then asked Kouki to go back with him but Kouki refused as he wanted to save Moana. Thinking that Kouki's delusional hero complex has returned, Hajime said that he would call Shizuku to give him a lecture but Kouki resolved himself to stay to save Moana. After the rest of Kouki's friends left the decision of Kouki's retrieval to Hajime, he wanted to confirm if Kouki thought that his choice was correct to himself, to which Kouki responded that such a thing didn't matter, an answer that impressed Hajime. Hajime then went to defend Arquette so Kouki could save Moana as he sent Kouki off with the aid of griffon Grim Reapers. When asked by their friends why Hajime lent Kouki his aid instead of dragging him back, it is revealed that Hajime was curious as to where Kouki (who has obtained an answer which is the opposite of Hajime) is going to end up. After helping defeat the "Dark Beings", Hajime was willing to grant Kouki's request of taking Moana with him.

Right after saving the world, however, Kouki was again summoned into another world, dragging Hajime along with him. It turned out that both were summoned into a sci-fi world by the combat-support A.I. G10 by coincidence. During their time in the other world, both of them worked together when both of them were summoned into another world, where they fought against an evil A.I. with the help of G10 (another A.I.), Kousuke (summoned by Mother), Noint/Netemp, and others.

After Mother's defeat, Kouki, Hajime, and Kousuke both got summoned again. This time, the goddess named Aularodde Lea Refeat summoned them.

Ryutarou Sakagami
Ryutarou is one of Kouki's closest friends. Kouki and Ryutarou have known each other for a long time and have a deep bond. Kouki knows that he can always count on Ryutarou to support him and Ryutarou will always try his hardest to stand by Kouki and his friends to try to help them. While the two have a good relationship, Ryutarou is secretly jealous of Kouki due to Ryutarou being weaker then Kouki and due to Kouki being perceived as a main character who gets all of the fame and women to fall for him compared to Ryutarou who is just there to support the main character. However despite this jealousy, Ryutarou still cares for Kouki and genuinely sees him as his oldest dearest friend and desired to obtain enough strength and power to "beat some sense back into him" when he began to lose his way.

Kaori Shirasaki
Kaori is one of Kouki's closest friends. Kouki has always respected Kaori for being a kind person. But due to his denseness, he never notices that Kaori loves Hajime and thought she felt bad for Hajime who is always alone. More than once, he doesn't realize that what he says hurt Kaori more than help her, such as after Hajime fell into the abyss. When Kaori confesses to Hajime and declares that she would be going with him, Kouki couldn't believe or accept it that she really loved Hajime the whole time. Kaori does not want to be with Kouki romantically as he is upsetting her and thus refused to return to him. Later upon mentally hitting his breaking point in the final trial of the Frost Caverns of Schnee while battling his doppelganger, Kouki came to the delusional and convenient conclusion that Kaori did not truly love Hajime, but was instead "brainwashed" by Hajime into loving him. He later brazenly proclaimed that she along with Shizuku "belonged" to him due to their childhood friendship, that he interpreted as romantic love, causing him to try and kill Hajime to "free" her. However in the end Kouki only ended up hurting Kaori's feelings even more when after his second defeat by Hajime, he insolently wondered if it would have been better if he himself fell into the abyss instead of Hajime so that way he would have Kaori for himself, causing her slap him in the face for tactlessly disregarding how much emotional pain that event had caused her coupled with his so-called "righteousness" of trying to kill Hajime before begging him to stop his stubborn self righteous madness before she starts hating him. After he gave up his attempts of defeating Hajime, Kouki also gave up on his love for Kaori as he now fell in love with Queen Moana de Shelt Synclea along with accepting the fact that Kaori was truly in love with Hajime from the beginning and that she would not return his affections.

Shizuku Yaegashi
Shizuku is one of Kouki's closest friends. They have known each other when they were little and are usually seen together. However, unlike Ryutarou, who blindly supports Kouki for the most part, Shizuku usually tries to get Kouki to think before acting. At times, Kouki will open up about his feelings to Shizuku, but much to his dismay, she tends to point out where he's wrong rather than telling him what he wants to hear. After Kaori decided to travel together with Hajime, he pleaded with Shizuku not to leave him too, which she doesn't promise. Shizuku usually mediates the conflict between Kouki and Hajime as Kouki continuously clashed with Hajime's choices during their travels. Later upon realizing that Shizuku also bore romantic feelings for Hajime, Kouki could not believe or accept it, as he had believed that Shizuku promised to never leave him when she agreed to look after him and the rest of the hero party. This caused him to delude himself into thinking that Shizuku was in love with him, eventually causing him to conveniently interpret this situation as Hajime "brainwashing" her to love him, leading him to willingly attack and fight against Shizuku in order to "save" her and was even willing to resort to extreme and possibly fatal force to accomplish this. However, despite this violent behavior, Kouki still saw her as a friend and promised to help her recover after defeating Hajime and "freeing" her. Later upon being defeated by Hajime once again Shizuku clarified to Kouki that while she does indeed love him, it is instead as something akin to a troublesome younger brother for her to look after rather than an actual lover, thus repairing their friendship. However Shizuku also made it clear she wasn't asking for his blessing in regards to her feelings for Hajime and was simply telling him because he's her childhood friend. Following his defeat, Kouki gave up his romantic feelings for Shizuku and let her be with Hajime as Kouki found a new lover named Moana de Shelt Synclea. Unknown to Kouki, his spoiled bratty sister, Mitsuki tried to destroy Shizuku's wedding photo shoot with Hajime only for her to be bullied and humiliated by Hajime.

Kousuke Endou
At first, not much interaction was shown between them, except that they were both part of the Hero Party. However, in the After Story, Kouki can be quite harsh on Kousuke whenever he acts weird, something that Hajime and himself can both agree on. This is evident when Kouki cut open Kousuke's stomach to remove the bomb Mother implanted instead of reprimanding Hajime, much to Kousuke's dismay. Also, when both Hajime and Kouki get into a catfight (similar to Yue and Kaori), they both punch Kousuke when he tries to calm them down. Of course, Kouki also tends to ignore him and his whining.

Eri Nakamura (deceased)
Eri see's Kouki as her savior and will do anything for him to be hers. Eri has harbored an obsession with Kouki ever since he saved her from commiting suicide when she escapes her abusive mother. She has harbored love for him since that moment and was thrilled to come to Tortus where she had the opportunity to make Kouki hers. During Cattleya ambush of the Hero party, Eri was willing to sacrifice all of her classmates if it meant that she and Kouki would be safe. She later betrayed the Heiligh Kingdom and her classmates to the demons if they promised to spare her and Kouki. Kouki was at first unwilling to believe that the seemingly kindhearted girl he knew would betray him and his classmates but was forced to accept reality after Eri revealed her schemes and was forced to accept the truth when Eri retreated with Freid and Aiko revealed Ehit's nature as an Evil God. When Kouki snapped at the Frost Caverns of Schnee, he thought Hajime also had "brainwashed" Eri as well, believing he was the reason why she betrayed them.

Daisuke Hiyama (deceased)
Before being transported into Tortus, Kouki was bothered by Daisuke Hiyama's lust of Kaori. After the Hero Party in the Great Orcus Labyrinth escaped the trap that Daisuke accidentally activated due to his carelessness, Daisuke prostrated himself in front of the Hero Party and Kouki especially as he knew that due to Kouki's hero complex, Kouki would easily accept his apology and smooth things over with the rest of the party. Following Daisuke's betrayal by siding with Eri and Ehit to massacre him and his classmates and the Heligh Kingdom knights including personally killing one of his best friends Kaori to make her his undead slave before his eyes, Kouki holds a hostility on Daisuke for his treachery. However, Kouki was not pleased when Hajime brutalize Daisuke before tossing him to be devoured alive by the demonic monsters. Furthermore, when Kouki blamed Hajime for not warning them of Ehit's schemes earlier that allow Eri and Hiyama to betray them, Hajime coldly reminded Kouki it is his delusional idealism at fault he and his classmates had nearly died and it was precisely Kouki's naive expectations that fellow classmates must be obligated to help and protect each other that had allowed even an idiot like Daisuke to manipulate and betray him without ever realizing it, which Kouki bitterly acknowledged and could not deny. Hajime also warned Kouki if he intends to continue test his patience by trying to enforce his misguided justice onto him and his friends, he will meet the same fate as Daisuke. After Hiyama's death, Kouki (like everyone else) considered that's what he deserved. When Kouki became corrupted in the Frost Caverns of Schnee, he still condemned Hajime for murdering Daisuke despite that fact Hiyama was technically a traitor which is due to his delusional justice.

Ehit (deceased)
Ehit had chosen Kouki to be a potential vessel and thus blessed him to be the strongest out of his summoned Heroes by giving him the Job Class of Hero as well as having the highest stats and most amount of Skills out of his classmates. Kouki, due to his misguided sense of justice and inability to differentiate between good and evil, proved to be one of Ehit's most easily manipulable pawns. Kouki's delusional ignorance led him to train hard in preparation to participate in Human-Demon War and even attempted to recruit Hajime's extremely powerful party members, Yue, Shea, and Tio to joined him in fighting for Ehit. After learning from Aiko of Ehit's true nature as an Evil God and his manipulative schemes of using his entire class as pawns for his game of death including the fact that Eri had personally exposed how Ehit had helped her in betraying them through sending Noint to abduct Aiko along with brainwashing both King Eliheid and his nobles during her death trap, Kouki was begrudgingly forced to accept the truth of Ehit's evil nature.

After the demons retreated from the kingdom, Kouki angrily blame Hajime for not warning him during their reunion in the Great Orcus Labyrinth about Ehit's true evil nature that lead to Eri and Hiyama's betrayal and the demon invasion of the Heiligh Kingdom. Hajime however, simply stated that Kouki himself will never wanted to believe that Ehit whom the humans of Tortus had worshiped, who had also specially chosen him to be the "hero" is in reality an evil god and all his efforts in fighting for Ehit were meaningless, instead he would just get angry at Hajime for supposedly slandering Ehit, a fact which Kouki could not deny. After being told by Hajime that he has no desire to save the people of Tortus from Ehit's manipulations, Kouki affirmed that he would save Tortus by obtaining the power of Ancient Magic to defeat Ehit and demanded that Hajime take Kouki and the rest of the Hero Party with him to conquer the last two remaining Great Labyrinths.

Despite already learnt of Ehit's schemes including the fact that he was never a chosen hero, Kouki still stubbornly cling onto his privilage and prestige as Ehit's chosen hero due to his immense arrogance and hero complex, as he still self-righteously insist all people should revere him and obediently follow his orders and ideals due to him being the hero, resenting that Hajime is not only far stronger than him and being well respected by Tortus inhabitants such as the Haulia Tribe, Verbergen, Dukedom of Ankaji and Hoelscher Empire despite not being the chosen hero, but also getting absolutely love and adored by a harem of rare beauties instead of himself, and angrily lashed out at Hajime for refusing to follow his justice and ideals.

Upon being corrupted in the Frost Caverns of Schnee, Kouki angrily blamed Hajime for his own failures by saying that Hajime interfered with his heroic efforts to save Tortus as Ehit's chosen hero. This however simply proves that deep down just as Hajime correctly stated before, Kouki does not wish to believe that Ehit is an evil god and angrily lashing out at Hajime for slandering Ehit and declaring that he will make Hajime's friends to join him in saving the world in Ehit's name but ended up to yet another swift defeat by Hajime.

Ehit revealed that he summoned Kouki as a pawn in his game to balance the board by helping the Human side since Freid obtained the power of Ancient Magic. He also had plans of making Kouki his host body due to his delusional naivety making him so easy manipulate before he rediscovered Yue. After his second easy defeat by Hajime however, Ehit now deemed Kouki to be useless to him since the so-called "hero" is too weak of any real use to him when he was defeated by Hajime so easily after he captured and temporarily possessed Yue's body. Ehit has instead decided to use Kouki as a "prize" for his new servant, Eri Nakamura for serving him so well when she brought him Yue.

Dark King (deceased)
The person who ruled over the "Dark Beings" until he was slayed by Kouki. Initially, Kouki wanted to spare him, but never came to pass as the Dark King was just too evil.

MOTHER (A.I.) (deceased)
The self-proclaimed 'goddess' of the sci-fi world and the most advanced A.I. there. She saw both him and Hajime as viruses and tried to capture them by summoning Kousuke, only for it to backfire on her. She also found it frustrating to see the 'incompatible duo' keep messing up her plans. During the decisive battle, Kouki used all the sword skills he knew and powerful light magic to wipe out most of the approaching machine soldiers.

Meld Loggins (deceased)
Meld pays special attention to Kouki due to the latter's vocation of "Hero". He would begrudgingly prioritize his safety over the safety of the other students. After the fight against Cattleya in the Great Orcus Labyrinth, Meld apologizes for not teaching Kouki that he will have to be ready to kill his enemies when the time comes, a mistake that almost cost Kouki and the others their lives because Kouki failed to bring himself to kill the demon when he had the chance. When Eri later uses Meld as one of her undead soldiers, Kouki was shocked and saddened to see what had happen to his mentor because Meld was the person who helped Kouki the most. Despite knowing Meld was already dead, Kouki couldn't bring himself to strike him down and end up hesitating too much.

Moana de Shelt Synclea
Moana is the Queen of Synclea Kingdom that Kouki is summoned to in order to save her people from a race of creatures called the "Dark Beings". Moana quickly establishes a friendly relationship with Kouki who is the hero that Foltina summoned even asking him to call her casually with him being reluctant to do so at first. Moana notices that Kouki is struggling with some internal conflict as they discuss what it means to be a hero as she later apologizes for forcing Kouki to kill for the first time, seeing as it traumatized him a bit. She acknowledged his kindness but Kouki vented his feelings self-loathing as he told her that he is scared of himself as he cannot trust his own judgement. When he heard how she risked her life in a climatic battle against the "Dark Beings" while straining her health to protect her kingdom, Kouki stated that he admires her. When they were staying the capital, they discussed their motivations and reasons for fighting, they growing closer as Moana stated that the two of them are the same since they want to keep fighting for the sake of others no matter what happens to themselves. After Kouki stays behind to defend Arquette, Moana rallies reinforcements to support him as she would not let him die while he was fighting for her kingdom's sake. When she witnesses Kouki, who was nearly fatally wounded as he had cut down several thousand Dark Beings for the sake of of protecting the people of Arquette, she became tearful and enamoured with him. As Kouki was recovering from his injuries, Moana hugged him as she was relieved that he survived. When Kouki told her that he had found his answer, Moana promised that she would support his choice no matter what it was as she wanted to become his strength, as Kouki started calling her by her name and talking to her casually. When Moana attempted to confront the "Dark King", Kouki was able to come to her side, rescuing her and defeating the "Dark King" thus ending the threat of the "Dark Beings".

Moana decided to accompany Kouki back to Tortus, where she adventures beside him while engaging in cat fights with Aularodde Lea Refeat that also fell in love with Kouki.

Aularodde Lea Refeat
The former Goddess is one of Kouki's two companions and lovers. They first met each other when she summoned him along with Hajime, Kousuke and the two ex-apostles: Etemp and Netemp. Like all the other gods and goddesses, she begged the hero, Kouki, to save the world from danger. She was surprised by Kouki telling her to save the world instead of him, probably due to the stress built up in him for being summoned three times already.

At some point, she fell in love with Kouki and had cat fights with Moana which caused Kouki to be annoyed.

G10
The A.I. responsible for summoning him and Hajime into a sci-fi world, which was not meant to happen.

Hajime's Harem
Aside from Kaori and Shizuku, Kouki also holds an immense lust for Yue, Tio and Shea due to their extremely rare and captivating beauty which are on par with Kaori and Shizuku. Along with his delusional pride and childish ideals, Kouki foolishly thinks Hajime has mistreated them and offered them to leave Hajime and join him for "better treatment". However, due to their love for and loyalty to Hajime alone, they are absolutely disgusted by Kouki's self-righteous ignorance and bluntly rejected his idiotic offer immediately, with Yue insulting Kouki in sheer disgust. Kouki then foolishly challenged Hajime to an unarmed duel to trying to take Hajime's friends by force until the latter easily defeated and humiliated him when he simply dropped Kouki into a pitfall filled with non-lethal grenades, ending the pointless duel. Their undying love and devotion for Hajime immensely increased Kouki's jealousy towards Hajime as he secretly believed that he himself is more fitted to be their lover due to his misguided justice and delusional pride in his status as Ehit's chosen hero compared to Hajime as pointed out by his Schnee doppelgänger. In the Frost Caverns of Schnee when Kouki became corrupted, he delusionally believed that Hajime had "brainwashed" his friends into loving him (which he never did) and decided to claim them for himself under the pretext of "freeing" them by killing Hajime and forcing them to join him in saving the world for Ehit, but ended at yet another stunning failure when he was effortlessly defeated by Hajime once again and ultimately failing his designated trial to claim Ancient Magic. For Hajime's friends themselves, they viewed Kouki in his corrupted state to be beyond pitiful and after his second defeat by Hajime, both Yue and Shea have shown their wrathful sides as they wanted to kill Kouki for attacking Hajime which caused him to be terrified of them only for Hajime to order them to leave Kouki be for the sake of Kaori and Shizuku.

Holy Church and Heiligh Kingdom
Due to Ehit choosing Kouki as his chosen hero, the Holy Church and all the Heiligh Kingdom nobles even the King Eliheid S. B. Heiligh treated Kouki with absolute respect, admiration and reverence as their God's chosen savior which Kouki became absolutely proud of, giving Kouki their most powerful artifacts for his personal use. It was due to this experience that he became being greatly offended when Emperor Gahard criticized him for his lack of resolve (like Hajime did) instead of praising him. Kouki himself would blindly trust the Holy Church and Heiligh Kingdom, in particular their fanatic religious worship of Ehit to which Kouki will get mad at Hajime if he were to expose Ehit's true nature as an evil god which he would interpret as slandering the god, even criticizing Hajime for not rejoining them in their war against demons. He then attempted to persuade and later force Hajime's comrades Yue, Shea and Tio whom are from races discriminated by the Holy Church to join him in fighting for the Holy Church and Heiligh Kingdom's religious war for Ehit. Even when the Holy Church and Heiligh Kingdom branded Hajime a heretic and allowed Noint to abduct his teacher Aiko, Kouki still believed that the judgement of the Holy Church and Heiligh Kingdom was right. It was only after Eri's betrayal and the demon invasion of the Heiligh Kingdom, did Kouki started doubting them though was immensely frustrated when Aiko exposed Ehit's schemes in which all the Hero worship Kouki had received from the Holy Church and Heiligh Kingdom was nothing more than a fabricated lie meant to manipulate him for Ehit which incredibly damaged Kouki's pride.

After Ehit's death, the survivors of the Heiligh Kingdom and the Holy Church who sided with Hajime to defeat their former god, stopped respecting and idolizing Kouki and the Hero Party, as they learned of the lousy work they had to complete the labyrinths, along with the betrayals of Hiyama and Eri, because of Kouki's idealism. With that, the Heiligh Kingdom and the rest of the Holy Church began to consider the Hero Party as the weakest party, and they also idolized Hajime and his party for defeating Ehit, and for their excellent work in completing the labyrinths.

Etemp and Netemp
The spider golems with the souls of apostles that were initially killed by Hajime and Shea. Both accompanied Kouki and Hajime in the sci-fi world, where numerous comedy-skits occured.