Genya Shinazugawa/Relationships

Sanemi Shinazugawa
Sanemi is Genya's older brother and only living sibling. Initially, they got along well as they worked together to help their mother. After a Demon attack befell their family, Sanemi and Genya were the only ones who survived the incident. However, after Genya branded his sibling a "murderer", their relationship began to worsen and decline until the two split and went their own ways. It is revealed during the battle with Kokushibo that despite the whole incident, Sanemi still heavily cared for his younger brother and actually wanted him to live a normal life without the threat of demons; Genya is moved to tears and apologized after hearing Sanemi's reasoning behind his rudeness. After their battle with Kokushibou, a mortally injured Genya apologized again for blaming Sanemi and thanked his brother for protecting him before succumbing to his wounds and crumbling into dust, leaving Sanemi stricken with grief.

Tanjiro Kamado
Tanjiro and Genya's first actual interaction took place at the end of the Final Selection, when Genya mistreated Kanata Ubuyashiki and Tanjiro stopped him. At first, Genya treated Tanjiro like an annoying pest and wouldn't even talk to him. This didn't discourage Tanjiro who kept wanting to connect to Genya, pissing him off. However, throughout their fight with Hantengu, Genya started befriending Tanjiro and gains respect for him. Tanjiro also tried to mend Genya's relationship with Sanemi, although his actions earned him a mouthful from the higher-ups. Genya later taught Tanjiro how to do repetitive actions during Gyomei's Hashira training, and later Tanjiro cries when he hears of Genya's passing.

Gyomei Himejima
In the data book, it says that Gyomei took Genya in as a "step son". The 2nd Fanbook gives more background towards their relationship. It revealed that Genya was rescued by Gyomei when he went out of control after eating a demon. Genya stubbornly decided to follow Gyomei and continuously asked the latter to take the former in as their Tsuguko. Although Genya wasn't blessed with talent and has a bad temper, he got along well with Gyomei, the latter acknowledging him for his honesty and willpower.

Inosuke Hashibira
Genya isn't seen often interacting with Inosuke. Once Genya befriends Tanjiro Kamado, he generally respects his friends. But, in the manga, him and Inosuke are seen fighting because Inosuke mocked him because he could not do any breathing styles (which is why he uses a gun instead).