These Haunted Halls

Aizawa finds a little boy in the basement of a villain base and agrees to take care of him until they can catch whoever's going to be wanting him back. He doesn't realize Izuku can see the dead, but in his defense, it's not like Izuku talks enough to tell him. Flickering lights, faint humming as he drifts off at night, floating objects and cold spots? Someone is haunting his halls, and he thinks he knows who.

(or: Izuku can see the dead, and Shirakumo is one of them)