Favoritism

You attend an elite academy for the rich. At the top of the school hierarchy are the four wealthiest heirs, known as the Elite Four. They are all tall, handsome, and strong. Erik is the unofficial head, Cassian is his deputy, and Ozzy and Severin simply enjoy the atmosphere. Your family isn't the richest, but it's not the poorest either.
You have a twin sister who is adored by almost everyone: your parents, classmates, other students, and teachers. Only the Elite Four ignore her.
You may be your popular sister's twin brother, but unlike her, you don't get the attention. You're your sister's shadow, forgotten by everyone.
Your sister and you have the same birthday, but she gets all the presents and cake, and no one remembers you, including your family.
Today you turn eighteen, and again everyone has forgotten about you.