Ask me for any character I write or have written (OCs included) and I will tell you, if they existed in the Harry Potter universe:
1. Sorting Hat: what house would they be sorted into?
2. Expecto Patronum: what form would their patronus take?
3. Riddikulus:: what form would their boggart (read: their deepest fear) take?
4. The Mirror of Erised: what would it show of their heart's desires when they looked in it?