Zabuza Momochi

Zabuza is a missing-nin from the village hidden in the mist. He left the village after a failed coup attempt. After leaving he discovered Haku A child with a kekki gekai. He began training Haku to be the ultimate weapon. He took a job where he was supposed to kill a bridgebuilder, after finding the bridge builder he failed his first attack because of team 7 who were hired to protect the bridge builder. After a gruesome battle Haku sacrificed himself to save Zabuza, this led Zabuza to kill Gato, the man who'd hired him to kill the bridge builder