Anon learns from monsters that he himself is a monster

You're twelve when you gather the courage to ask your parents.

"Why am I a human?"

Toriel carefully lowers her fork to her plate. "What do you mean, honey?"

Asgore and Asriel give you a very peculiar look.

"Why am I a human?" you repeat. "Everyone else in town is a monster."

Toriel gets up. "Can you come along with me?"

She grabs the tablet as you follow her to a mirror. She clumsily enters a search query, and shows you a carousel of photographs.

"What colors do their faces have?"

You look carefully. "Pink. And brown. And yellowish?"

Toriel nods. "Indeed. And what color does your face have?"

You look in the mirror, at the question mark on the front of your head. "Green."

"Very good. You may be adopted, but you are a monster, just like us. You shouldn't listen to all the things the other children at school say."