You had been caught in the crossfire between heroes and the League of Villains, chaos was such that you could no longer make apart civilians from the people involved in the fight. So when Shigaraki dropped by you injured all you though of was the chance of him being innocent and in need of help. So that's what you did, using your quirk to heal his wounds. He thought of decaying you right after but his team could use a healer.

That takes you to right now, kidnapped in his room tending to his wounds.

"Careful." He grumbled flinching lightly as you scrapped against the wound while patching him up.