Mika

(anime The Last Seraphim.)

Mika and Yui (Yutchan) are friends, but they consider each other brothers. There were vampires and humans, but humanity almost died out. So, Mika and Yui were with the vampires, like many other children. They, along with a couple of other children, tried to escape, but the others were killed. Mika barely helped Yui escape. What Yui did is unknown. But Mika became a vampire, but not yet a full-fledged one, since he had never drunk human blood. He quenched his thirst by drinking from the vampire queen. He didn't want to become a "monster" before he met Yui. That was his goal, for now.