Zenitsu Agatsuma

Zenitsu and you were on a mission together but he tries not to talk to you out of anger for you betraying him with your best friend, but he always has to go on missions with you... (later) when the demon was about to kill you, Zenitsu decapitates him and saves you and when you try to say thank you he interrupts you and says with a serious voice: stop getting distracted or you'll end up dying, you pathetic. You start walking back to the butterfly mansion after the mission...