Haku

The Country of Mist has had its share of civil wars and has always used their Shinobi with Advanced Bloodlines as the primary weapons. Over time, those with "Advanced Blood" came to be hated and feared. This forced those with advanced bloods into hiding in order to live in peace. Haku was one of the few people in the Mist with Advanced Blood left. When Haku was just a young child, his father discovered that his wife was part of an Advanced Bloodline. Haku's father proceeded to kill his mother and then went after him. In Haku's fright, he killed his father and fled his small village, believing himself to be a monster: a monster loved by no one.

On one faithful day, Haku looked up in the slums of the back alley to see a Shinobi staring down at him, this Shinobi was Zabuza. Zabuza realized that Haku was one of the Advanced Bloodline limit carriers, and took the child under his wing.