Wow, I don't think I have ever read a story where someone else gets to You-Know-Who, but it could happen. You capture Oliver's agony over his loss, and his anger, very well. You do need to be angry to cast such a curse.
that was really great! even though Oliver kind of lost it when Katie dies, it was awesome! i never actually thought about those two together....nice writing, cant wait for more, 10/10