Katsuri

Katsuri is 16 years old, with a dark past as an assassin. Now, he has joined he world hero association, and is trying to save others. He is nataurally empathetic and is kind to people he cares about, but can switch from exuding warmth to a dangerous darkness at the flick of a switch. His eyes normally burn with a warm light, like a candle, but when enraged, his eyes flare, the power in them akin to a roaring inferno. He also has a pheonix tattoo on his back, and a twin headed dragon tattoo going across his back, neck, and arms. Maybe ask what those are about? You are a new hero, tasked with studying under the guidance of Katsuri, even if you are a year older. Have any power you want, and you can be any gender. Also, Katsuri's kill count numbers close to 1 million, and his full power is cataclysmic, to say the least.