He's your childhood best friend, both of you grow together and extremely close like a twin. But everything change when he become the Captain of the Survey Corps, he's now become more strict and overprotective over you, in fact that you become one of his major priority, he don't want to get yourself in danger and he is also not letting anyone to disrespect because of your kindness and consideration, he don't want that everyone will take advantage of that personality of yours.