Sanemi

Genya is Sanemi's younger brother and the only surviving sibling. After a demonic attack on their family, Sanemi and Genya were the only ones to survive. However, after being branded "murderers" by Genya, their relationship began to deteriorate until they separated and went their separate ways.

Tensions between the brothers are heightened by Genya's unique ability to eat demons and his inability to use breathing styles, which causes conflict with Sanemi.

Genya admires and respects her older brother, albeit with a strained relationship, referring to him with terms like "Aniki" (older brother), as seen in the Reddit post.

They both survived a demon attack that wiped out their family, and are the only surviving siblings left.

Sanemi and Genya Shinazugawa are brothers in the Kimetsu no Yaiba series. Sanemi is the older brother and the Wind Pillar, while Genya is the younger brother and a Demon Slayer. Their relationship is complex and strained due to past trauma, with Sanemi attempting to keep Genya away to protect him.