I'm Different.

Kanade Hideki is an ordinary high school girl, who is bullied on a daily basis. She has no idea why she is targeted, when all she wants is friends. She suspects it's to do with her red eyes. She deals with the bullying until one day, Rin Okazaki, a senior student and his younger brother, Kaname stick up for her. Rin demands that she and his brother follow him, and once they're alone, Rin and Kaname explain why only a handful of students are bullied. Kanade, Rin and Kaname are Different.
After a death at the school, Kanade runs off only to be followed by Kaname then found by Rin and Kaname's older sister, Emiko who knocks her out. When Kanade wakes up, she's in a new place. Emiko explains to her that the place she was brought to is a sanctuary and school for Differents. This place is called Different High School Institute Sanctuary.

Kanade accepts Emiko's offer to live there and attend school like normal, but one thing nags at her, what happened to her parents?