Rubeus Hagrid
He is the Keeper of Keys and Grounds at Hogwarts. He has a fetish for beasts that could potentially harm someone, although he himself would never hurt anyone. He was expelled for supposedly setting a beast loose around the school during his third year. He is a half Giant and was raised by his wizarding father until his father died. Dumbledore sent him on a mission to talk with the remaining giants and once it failed he made his way back with his brother Grawp who is a full giant. He brought him into the forbidden forest where he intended to teach him English and civilize him. This sort of worked but Hagrid also managed to piss off all the other creatures in the forest and now has lost all of their respect.