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. Though, after Kouki lost his way, 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 & Shizuku Yaegashi
They are his childhood friends and fellow Returnee group members. Ryutarou only considered them as a friends (unlike Kouki). Ryutarou allowed them to be in love with Hajime after learning of his survival and how he obtained monstrous strength, as he did not want to get on Hajime's bad side after he murdered Hiyama.

Hajime Nagumo
Ryutarou originally thinks very 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 her time on someone who is a failure. Even after his class is summoned to Tortus, this fact doesn't change for him. And similarly to Kouki, he also easily accepted Hajime's supposed death after his fall into the Abyss. In Volume 4, after being rescued by Hajime from the attack from the Demon Cattleya and her army of Monsters and seeing that Hajime has changed by becoming ruthless against his enemies, Ryutarou became afraid of Hajime after hearing his claim that he was willing to kill anyone, including his former classmates, who dare to cross him or harm his friends. Like most of his classmates, he takes Hajime's warning seriously to ensure his own safety and to not get involved with Hajime's bad side after he brutally murdered Hiyama. But he doesn't condemn Hajime for it, as Ryutarou will never forgive Hiyama for what he had done.

After Hajime revived Kaori, Ryutarou expressed his gratitude to Hajime and his respect for him and his immense strength.

In Volume 6, after the Demon Invasion and learning the truth about Ehit, following both Eri's betrayal and Hiyama's death, Ryutarou, Suzu, Kouki, and Shizuku managed to convinced Hajime to give them a second chance to join him and his companions to clear the remaining Labyrinths and destroy Ehit. After Eri's betrayal and Hiyama's death, Ryutarou (as well as Suzu, Shizuku and Kouki) travelled with Hajime and his companions, while the rest of their classmates stayed behind to protect the Heiligh Kingdom.

In Volume 9, when Hajime began to enhanced his classmates' armor 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 tested & witnessed the destructive power of his gauntlets' new enhancements. He exhibited surprised in Hajime's creations since they're similar to the military/army's' armaments and technologies. Since Ryutarou admires military soldiers, and he is highly amazed by Hajime's firearms and military vehicles. He 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 , Ryutarou had begged Hajime to train him as he called him a friend which Hajime got touched by and accepted to train him.

While Hajime became more popular with beautiful girls than Kouki, Ryutarou doesn't hold any jealously towards Hajime. Unlike Kouki, Ryutarou valued his friends instead of pride, as he let Kaori and Shizuku to be together in love, with Hajime. Due to Hajime's superiority, Ryutarou also considered himself to be a lot weaker than Hajime when he doesn't have any power compared to Hajime's abilities after he murdered Hiyama.

When 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 sympathetic for Hajime. He also gives more respect and appreciation to Hajime's willpower, understanding that neither he or the others could have overcome the harsh Abyss like Hajime did, and Ryutarou realized how easy they had it, compared to him.

After returning to Japan, Ryutarou appreciated Hajime for all he had done for him and their 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 instantly 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 finds annoying.

Ehit (Deceased)
Ryutarou once respected the so-called "God", Ehit after he was summoned and blessed as one of his so-called "Heroes". However, after learning from Aiko and Princess Liliana of Ehit's true nature as an Evil God, Ryutarou turned against Ehit and sided with Hajime now that he fully aware of how Ehit has been psychotic and filthy he is.

Daisuke Hiyama (Deceased)
Ryutarou hated Daisuke as he saw him as a creep and a jerk after witnessing his cruelty to Hajime both at school in Japan and later in Tortus. After Hajime's presumed death, Ryutarou was easily manipulated by Daisuke's lies. When Daisuke betrayed his classmates and temporarily killed Kaori, Ryutarou's disdain towards Daisuke increased even further. Though Ryutarou was fearful of Hajime's brutality when he easily murdered Daisuke, Ryutarou doesn't condemn Hajime for murdering Hiyama, as he chose to never forgive him for what he had done. When Ryutarou learned that Hajime's "fall" wasn't an accident, Ryutarou abandoned what was left of his sympathy and will always remember Daisuke Hiyama as selfish, deluded traitor.

Soul Sisters
Despite being Kouki's best friend, the Soul Sisters mistreated and tormented Ryutarou. Since he was viewed as one of the 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. She had planned an assassination plot to kill Ryutarou and the rest of her classmates due to him and the others standing in her way to make Kouki hers. Upon their reunion, Ryutarou exhibited in hostility towards Eri when she ignored Suzu and later himself due to her focusing her attention on Kouki.