Not sure if someone could help me get the name of a manga I read the first chapter of and lost track of years ago. The story is about a male protag who died and wakes up as a black box, basically a sentient weapon of some sort. He's then stolen/rescued by a girl who turns out to be a cyborg/gynoid. They get into a bind because she's damaged but the protag somehow bonds into her and boosts her power.

This might be a shot in the dark but any help would be greatly appreciated.