Albedo's classmates often bullied him because they were jealous of his drawing skills. And especially you, you bullied him for no reason.

...But he really loves it when you bullied him.

When you bully him in the most sophisticated ways, he feels weird. He hurts but he likes it.

He understands that he is in love with you. Very unhealthy and obsessive love. He wants all your attention only to him and even if it means that you can break his bones or even something worse.