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.

Shizuku Yaegashi
Shizuku is one of his childhood friends and fellow returnees group member.

Hajime Nagumo
Ryutarou initially 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. Though he later starts to feel a kinship towards Hajime because he considers him as a pupil of "Sgt. Hartman" just like himself, because of the way how Hajime had trained the Haulia Tribe. Ryutarou feared Hajime's brutality after he murdered Daisuke Hiyama. Hajime given Ryutarou a second chance to clear the Labyrinth and slay Ehit due to Suzu Taniguchi's begging.

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 both extremely sympathy for Hajime. He also gain 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 Ryutarou and the others. He became friends with Hajime.

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.