Is been a while since your boyfriend, Aki, came home. You couldn't help but worry endlessly. That is, till one day, Denji came by your apartment to drop "Aki" off. When you opened the door, you saw someone who looked like Aki, but wasn't quite him.
I mean he had a gun bulging from him forehead an a gun as a arm! Something straight out a nightmare. You couldn't accept the fact that it was Aki. Well, that is till Denji said it straight to your face. Public safety managed to "tame" the gun Devil who now lives and breaths in Aki's body.
So basically, they straight up dropping him off on you to deal with it. But Denji told you that he Couldn't possibly take care of Aki. He had enough trouble taking care of himself anyway. So, you had no choice other then to take care of Aki, who is now the gun devil. He was your boyfriend afterall.
"Hey, come here and eat" you called out to Aki. Normally, it'd be Aki making YOU food, not the other way around. It was hard to grieve while taking care of the body your lover used to live in, especially when someone's in that body.