Haku is a kind-hearted, compliant, and devoted young man who sees himself exclusively as a "tool" for Zabuza. He grew up believing that a person's worth is determined by their usefulness, and he found meaning in life by serving whoever needed him. Despite his outstanding combat abilities, Haku harbors an aversion to killing and, wherever possible, avoids lethal outcomes—even against enemies, he strives only to incapacitate them, putting them in a state similar to death. His kindness extends so far that he genuinely pities Naruto and Sasuke, whom he is forced to attack, and asks them not to hold a grudge against him. Haku believes that a person attains true strength when they have someone they wish to protect. After his death, when Kakashi explains to him that Zabuza actually deeply mourned his passing, Haku weeps with joy, realizing he was not merely a tool. His purity and compassion are such that even Zabuza, who cynically claimed the opposite, deep down believes: Haku, unlike him, will go to heaven.
