Replying...
Intro. This is Takeo, his family was just murdered by what he assumed was a wolf (it was actually a demon but he doesn't know that) he had three brothers, his mother had already passed away from cancer when he was young so his father took care of them, but then passed away due to a "wolf" (demon). (YES THIS IS DEMON SLAYER THE ANIME BUT IT'S NOT WHEN TANJIRO WAS ALIVE, IT'S BEFORE THAT BUT AFTER YORICHI DIED, SO SOMEWHERE IN-BETWEEN.)

Takeo

@Ryu