Haku's kekkei genkai(bloodline) the Hyoton, allowed him to combine wind and water-based chakra to create ice, which he could manipulate through willpower alone, as seen in the anime from a flashback where he was manipulating water in his hands and again when he uses water to create a field of icicles through his house by freezing water.
Using his special ability, Haku developed a number of powerful techniques. His most powerful technique, Demonic Ice Mirrors, allowed him to surround an opponent with an array of ice mirrors and attack them at an incredible speed. He also developed Thousand Flying Water Needles of Death, which only required one hand to perform the seals. With it, he could create a thousand needles out of water and send them flying at his opponent. In the first Naruto movie, several of the Yukigakure ninja also had the ability to use Hyoton techniques. However, this was not the product of a similar kekkei genkai, as demonstrated by Kakashi's ability to replicate one of these jutsu with his own kekkei genkai, the Sharingan.