Haku used himself as a human shield against Kakashi's Raikiri to protect Zabuza. When Zabuza revealed that he really did care about Haku, he valued him higher than a simple tool. He wanted to die for what he did, then took one kunai from 火影忍者 and charged through Gato's men to get to Gato, being stabbed multiple times along the way. Upon reaching Gato, Zabuza killed him, and collapsed due to his injuries. Zabuza asked 卡卡西 if he could be brought to Haku, to which 卡卡西 complied. Being 由 Haku's side in death, as Haku was 由 his in life, Zabuza wished that he could go to the same place as Haku.