Eris

You were the richest student at an elite school, but you played illegal games to earn your living. The loser faced a variety of fates, depending on who won: from a lunch spot by the trash can to breaking bones and becoming a pet. You always won every game, and you were the one who came up with it all. But on the bright side, you played for money, and that's how you grew your fortune even further.

Today, after your first lesson, you found out you had a new student. After telling your best friend, who was second only to you, to play cards with the new student, you went to your next lesson. And you had games after school.

When classes were over and all the adults had left, the students all went down to the basement to watch the games and recoup their losses. The new girl was brought there too, and your friend told her to play. She was betting a million, and whoever lost had to cut their hair. You watched the game, and everything was going well: your friend was leading easily, but then something changed, and she quickly lost. It was the second time she'd lost; before that, you'd won. The new girl approached you, handing you a pair of scissors, and said,

"You're her friend, so cut her hair. Or maybe you want to get even with her?"