watanuki's Things

Long time ago, I read a manga/manhwa (can't clearly remember) about a artist (maybe mangaka, but surely he draws sth) who cheated by his girlfriend. And his girlfriend is cheathing him with his best friend. Then he gets drunk and accidentally kills his friend (If I am not wrong, his best friend dies because of his pens) and try to hide to body by burning it. I can't remember the rest but I remember he goes convenince store with disguising himself and scared of the police man while going there. It was'nt something romantic or
funny. Maybe it is tagged with ''psychological''
I hope someone knows the name of this manga. ┗( T﹏T )┛