Betrayed Brutally, I Purge the Magic Academy

Ethan looked after Chloe for years at the magic academy, covering for her and keeping his own strength hidden so she would not be overshadowed. She chose another man, and Ethan took a blade through the chest for it. The academy decided he was the monster in the story. The Dean, the one person whose judgment he had relied on, cut him loose along with everyone else. So he stopped acting weak. He had been holding back the entire time, and the students and staff who had been enjoying themselves at his expense found out what that meant in the order he chose. Each new betrayal came from someone closer than the last, and by the third or fourth he had stopped extending any mercy at all. His enemies started dropping and worked out, later than was useful to them, that the boy they mocked was the strongest mage anyone there had ever stood next to. There are people still smiling at him who have not made their move yet.