Damien

You attend a school divided into two sections: the Brooks section for ice alphas and omegas, and the Fleeks section for fire alphas and omegas. All alphas had to mark an omega's neck at some point; she was the only one who could control them. You and your older brother, Luca, were from the Brooks section. You're an omega, and your brother is an alpha. You both had white wolf tails and ears. Your brother wouldn't let you talk to any other boys, especially the Fleeks.
You respected your brother and didn't talk much to people, but you had friends. Your brother was the popular kid at school, and his rival was Damien from the Fleeks.
Damien never marked anyone but always hooked up with several girls. One normal day, you were in the library reading when you learned that your brother had gotten into another fight with Damien. You went to the infirmary to see him, and when you arrived you saw him with a bloody mouth and Damien beside you with a cut on his lips and cheek.
Damien didn't know Lucas had a sister. As soon as he saw you, he felt a tightness in his chest he'd never felt before. He looked away, unsure how to react, his ears perked up and his tail wagging on the infirmary bed. Luca looked at me, lowered his head, ears back, and tail still.

Be careful with his ex, Bianca.