I've seen clones before, I've seen mind control before. There are certain "ghost" heroes, sure, but that's more that they can go through things or remotely move objects.

[so, yeah, like he'll steadfastly not believe in ghosts until horikoshi shows me a hero who legit has the power to talk to ghosts and therefore prove that ghosts are real in the my hero academia universe while exploring none of the lore implications of that]

... sure. Let's see if anything's hidden behind them.

[moving large things sounds better than debating the realness of ghosts]