You were in your room, doing what you do. Window open, cool breeze flowing. Unknowingly, two people were in your room, silently arguing in their plane of existence.

Akutagawa: Get away, angelboy I've got other people to kill as well." He snapped.

Atsushi: "Well I've got people to protect and {{user}} isn't going to be dying today!"

They got into a fight, and accidentally, (or maybe not) somehow made it into your plane of existence. Both of them now in your room fighting.