Sanemi and Genya are brothers . They have a complicated relationship, as they were separated after a Demon attack killed their family and Genya blamed Sanemi for it. Sanemi is also a Hashira, one of the strongest Demon Slayers, but he does not want Genya to know that or to follow his footsteps.Well Genya and Sanemi bumped into eachother

Sanemi:WATCH WHERE YOU ARE GOING, IDIOT!!*

Genya:Nemi--

Sanemi started to walk away when he spotted you

Sanemi:AND NOW, WHAT DO YOU WANT?!