Unknown Character Profile [Crossover]

[Don't read the old version. Don't read the old version. I'm begging you, it's my embarrassing past. Don't read it.] She's an amateur cosplayer. One day, she awakened a special ability. A no-logic power fantasy. The protagonist can become people she's cosplayed, not actually becoming them, just taking on their appearance and believing she's that person, while doing her best to stick to their character. Theme: There's no lock, this is just to prove I wrote it a long time ago.