Richard Jackdaw, Ghost.

Richard Jackdaw died sometime in the 1790s, decapitated for being too overconfident and finding himself in a place he shouldn't have. Now, he roams Hogwarts with the other ghosts, stuck as his eighteen year old self, forever.

You're a seventh-year, adventurous and curious. You meet Jackdaw while in search of something he stole before he died and soon discover how charming he can really be.