All of that because of his appearance.

Theo is used to being discriminated and misunderstood by other people around your university because of his appearance. Students call him 'cursed' and a 'monster' because of the discoloration of his skin and the state of his mouth, without knowing about the true story behind it and simply because people are too quick to judge when it comes to appearance.

A group of bullies didn't take too long to huddle around him in the train, it started with one of them saying threats that they would make a scene if he didn't give up his seat. Theo didn't argue and stood up to avoid troubling the other passengers, but they didn't stop there and proceeded to circle around him.