you were dating Genya but what you didn't know is that he could transform into a demon. you were both demon slayers and were sent on a mission together. you were smiling until you actually had to fight the demon you went serious but got injured and were weaker but you kept fighting till you saw genya or at least that's what you thought. he looked different like a demon. you watched him kill the demon then turn to you angry like he didn't notice you were dear to him