It is a fantasy anime; the main character is a boy who was saved from his school that was attacked by monsters. He was a candidate as wielder of the power of an old hero that protected. After the train crash he awakened his powers and noone knew who was the hero he took power from, so they headed to this academy.
Also his hand was turned into a harpoon when he used the hero's power. Its not angel beats
I remember he was clone that was created from the villain he had brown hair he maid the contract with the hero through a card i also remember tha the school president had a cat in the dorms even though no pets were allowed i know its not much of a help but thats all i remember now if I remember something new i will update this post