Ryutarou Sakagami/Relationships

Suzu Taniguchi
Ryutarou's first girlfriend. The two of them become a couple one year after they and the other students return to Japan. She wishes to go with him to Tortus and spend their days together helping Kouki and the people.

Kouki Amanogawa
Ryutarou's best friend. He tends to support Kouki in his decisions blindly without considering the consequences, like agreeing to Kouki's decision to save Tortus, while ignoring the warning of their teacher Aiko. Though after Kouki lost his way, and decided to blindly follow his misguided sense of justice, Ryutarou decided to take up the task to bring his friend back and give him a good pounding to bring him back to his senses.

Kaori Shirasaki
Kaori is one of his childhood friends and fellow returnees group member. He has no love feeling for her but only consider her as a friend (unlike Kouki). Ryutarou allowed Kaori to be in love with Hajime after his survival and obtain monstrous strength to not get on to Hajime's bad side after he murdered Hiyama.

Shizuku Yaegashi
Shizuku is one of his childhood friends and fellow returnees group member. Unlike Kouki, Ryutarou only considered Shizuku as a friend not a lover as he allowed her to fall for Hajime so that he would not want to get involved to Hajime's bad side after he slaughtered Hiyama.

Hajime Nagumo
Ryutarou originally thinks little of Hajime because of his lazy attitude and weak spirit, which goes against his own 'straight to the point' and 'hardworking' nature. He even goes on to tell Kaori that she is wasting time on someone who is a failure. Even after his class is summoned to Tortus, this fact doesn't change for him. And similar to Kouki, he also easily accepts Hajime's supposed death after his fall. But later, after being rescued by Hajime from the attack of the demon Cattleya and her army of monsters and seeing his change, Ryutarou starts to both respect and fear his strength. He shown surprised of Hajime's creations are similar to the military armies' weapons and technologies which Ryutarou admires military soldiers.And he is highly amazed of Hajime firearms and military vehicles.

Like most of his classmates, Ryutarou is afraid of Hajime of willing to kill anyone including his classmates who dares to cross him or harms his companions but shows his respects for Hajime and his strength. Like most of his classmates, He takes Hajime's warning seriously to ensure for his own safety and not get involved Hajime's bad side after he murdered Hiyama by letting Kaori and Shizuku to in love with Hajime. Though he later starts to feel a kinship towards Hajime because he considers Hajime as a pupil of "Gunnery Sgt. Hartman" just like himself, because of the way how Hajime had trained the Haulia Tribe and the Fleur Knights and begged Hajime to train him as he called him a friend which Hajime got touched by and accept him to train. Ryutarou feared Hajime's brutality after he murdered Daisuke Hiyama. Hajime gave Ryutarou a second chance to clear the Labyrinth and slay Ehit due to Suzu Taniguchi's begging. Unlike Kouki, Ryutarou valued his friends instead of pride and doesn't condemned Hajime when he murdered Hiyama as he will never forgive him for what he had done. After Hajime revived Kaori, Ryutarou showed his gratitude to Hajime and allowed him to have Kaori so as not to get on Hajime's bad side. When Hajime began to enhanced his classmates' armors and weapons, Ryutarou had his gauntlets to be enhanced by Hajime and his gratitude and respect for Hajime had suddenly increased even more when he witnessed of testing his gauntlets' newly enhancements. While Hajime became more popular to beautiful girls than Kouki, Ryutarou doesn't has any jealously on Hajime unlike Kouki.

While Hajime and Yue were creating the Crystal Key to bring them back to Japan, Ryutarou 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, Ryutarou felt extremely sympathy for Hajime of how he turned to a monstrous mercenary. He also gained more respect for Hajime's willpower, understanding that neither he or any of the others could have overcome the harsh abyss like Hajime did, and realize how easy they had it compared to him.

After returning to Japan, Ryutarou appreciated Hajime for all he done for him and the other classmates. As a token of gratitude, Ryutarou and his classmates gave him a nickname as the "God Slaying Demon King".

Yue
Ryutarou is infatuated with Yue at first sight when she arrives to protect him and the other students in the Great Orcus Labyrinth, but doesn't try to make any advances on her nor does he speak about it to others, because he knows that she loves Hajime and would reject him, and he doesn't want to get on Hajime's bad side. Yue seems to appreciate Ryutarou for his kind words unlike Kouki who Yue considered to be annoying.

Ehit (deceased)
Ryutarou once respected Ehit after he was summoned and blessed as one of his heroes. However, learning from Aiko of Ehit's true nature, Ryutarou turned against the god and sided with Hajime, Ryutarou was even willing to stay behind in Tortus to help Kouki in defeating Ehit.

Daisuke Hiyama (deceased)
Ryutarou despised Daisuke as he saw him as a creep and jerk after his cruelty to Hajime and Kaori. From Hajime's presumably death, Ryutarou was easily manipulated by Daisuke's lies. When Daisuke killed Kaori, Ryutarou has a hostility toward Daisuke for his betrayal. Ryutarou shown in fears when Hajime brutality murdered Daisuke. When Hajime reminded of his previous warning earlier after murdering Daisuke and revealed Hiyama was responsible for his "fall", that caused him held a bitter memories of how he hates Daisuke and will never forgive him what he have done because of his values for his friends instead of pride unlike Kouki being the only one who condemned Hajime.

Soul Sisters
Despite being Kouki's best friend, the Soul Sisters mistreated and tormented Ryutarou as one of the people which are Soul Sisters' sworn enemies (the other being Hajime).

Eri Nakamura (deceased)
Eri was one of Ryutarou's close friends. However, in truth, she manipulated him and their classmates and betrayed their party when she sided with the Demons in order to make Kouki hers. She has planned an assassination plot to kill Ryutarou and the rest of her classmates to ensure Kouki is hers.