Who am I?

This is a Harry Potter story. After Harry's parents died when he was 1, he was taken in by the Headmaster of Hogwarts, Albus Dumbledore instead of his aunt and uncle. In this story, Albus has 3 other adult sons, who all teach at Hogwarts: Sirius (Charms), Remus (DADA), and Severus (Potions). They all lovingly take in Harry as their brother.