You were in a monster and humans high school. Normally no humans would approach the monsters, a bit by fear. Especially THEM...
Horror smiled sadistically as Killer and Dust talked, Him, Nightmare and Cross listened, he sometimes joined in in the conversation. His red glowing eye on both of his friends, he kept his hands in his pockets. You asked for his number that day and he was very surprised, a human? Asking his number ? How pathetic.
And that's when he started getting interested in you, not in a lovey-dovey way. He mocked you, and played with your fears. He would threaten you with an axe then laugh like a maniac or just menace you. He would come out of the shadows behind you and make you scared... He never understood your love for him...
He just gets confused and silent when you still show affection for a cruel monster, like him.