Kouki Amanogawa/Relationships

Hajime Nagumo
At first, Kouki considers Hajime a bother, viewing him as constantly fawning over Kaori due to his convenient interpretation of her attitude towards him. Later, after their reunion in the Orcus dungeon, seeing him becoming stronger and surrounded by many girls along with Kaori, who eventually decided to follow Hajime, he became jealous of him. This also coupled with fact that both of them have different way of thinking. After being saved twice during the attack on the kingdom, rather than being grateful, he became even more jealous of him. Kouki was further upset that despite his immense power, Hajime didn't believe he need to uses his power for "justice" because that's not what he wants. Hajime for the most part views Kouki as a nuisance that he wants to avoid dealing with due to his naive mindset and troublesome habit of interpreting things to fit his worldview. It is due to these traits that Hajime decided not to reveal that the god Ehit who had summoned them to be heroes was a twisted Evil God that viewed living beings as playthings or the fact that Daisuke Hiyama attepted to kill Hajime, since Kouki's idealistic mindset would never allow him to doubt those who are praising him. Kouki bitterly acknowledged that he wouldn't have believed Hajime if he revealed the truth about Ehit. After Kouki and his party joined Hajime's journey to conquer the remaining Great Labyrinths, Kouki's idealistic worldview and his desire to save everyone clashed with Hajime's more pragmatic worldview and his desire to prioritize his desire to return home. Kouki repeatedly attempts to impress his ideals onto Hajime or lecture him about saving the world. While initially confident that he can easily clear a Labyrinth and become as strong as Hajime, he discovers how wide the distance between their strength is. 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.

He eventually snapped after seeing Shizuku with Hajime together and finally noticing her growing affection for the latter. During the final trial in the Frost Cavers of Schnee, he was forced to confront his worst personality traits in the form of a doppelgänger, who encouraged these self satisfactory delusions and taunted him further in his failures, shortcomings and his inability to see things for what they truly are. This eventually caused him to lash out instead of accepting and conquering these negative feelings and aspects of himself and acknowledging them, choosing to believe that Hajime was only a monster who brainwashed not only Shizuku, but all his other companions to get what he wanted in order to better fit into his delusional world view. While Hajime was annoyed by this, he chose to not to kill Kouki because it would have made Kaori and Shizuku sad. After waking up and calming down, Kouki felt bad about how he attacked Hajime. However, he still couldn't accept Hajime or Shizuku's feelings for him.

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 in the Great Orcus Labyrinth. Witnessing the pain, suffering and loneliness Hajime went through and his determination to return home, Kouki finally realized where Hajime's immense power came from and understood why he couldn't match him; because of the difference in resolves between 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 Ryutaro 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 Ryutaro being weaker then Kouki and due to Kouki being percieved 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 genuinly sees him as his oldest dearest friend and desired to obtain enough strength and power "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 falls into the abyss. When Kaori confesses to Hajime and declares that she would be going with him, Kouki couldn't accept it or believe that she really loved Hajime the whole time. Later upon mentally hitting his breaking point in the final trial of the Frost Caverns of Schnee 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.

Shizuku Yaegashi
Shizuku is one of Kouki's closest friends. They have known each other for around 10 years and are usually seen together. However, unlike Ryutarou who blindly supports Kouki, Shizuku usually try's to get Kouki to think before acting. At times, Kouki will open up about his feeling to Shizuku, but to his dismay, she tends to point out where he's wrong rather than tell him what he wants to hear. After Kaori decided to travel together with Hajime, he plead Shizuku not to leave him, which she doesn't promise. Later upon realizing that Shizuku also bared romantic feelings for Hajime, Kouki could not believe nor accept it, as he had believed that Shizuku promised to never leaving 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, 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 from Hajime. Later upon being defeated by Hajime, Shizuku clarified that she does indeed love him, but not in the sense as a lover, but something akin to a troublesome younger brother, once again repairing their friendship. However, Shizuku 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.

Eri Nakamura
Eri see's Kouki as her savior and will do anything for him to be her's. Eri has harbored an obsession with Kouki ever since he saved her from commiting suicide to escape her abusive mother. She has harbored love for him ever 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 kindhearted girl he knew would betray him and his classmates but was forced to accept reality after Eri revealed her schemes. When Kouki snap at the Frost Cavern of Schnee, he though Hajime had "brainwashed" Eri as well, believing he was the reason why she betrayed them.

Meld Loggins
Meld pays special attention to Kouki due to the later'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 sadden to see what had happen to his mentor. 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 another world that Kouki is summoned to in order to save her people from a race of creatures called the "Dark Beings". The two of them develop a mutual attraction for each other, and she now accompanies Kouki on his journeys in Tortus.