After Haku (fem) was hit by Kakahi's chidori, she didn't die. You see, before she was sent away to another world, she was known as Harriet Potter, so her magic saved her. This temporary death served only 5o kill off the horux embedded in her scar. Without meaning to, she also saved Zabuza. Her magic healed him and kept them both alive when they were buried by Team 7. Now, they're in the magical world, trying to find a way back home. Zabuza x femHarryHaku