In Polynesian mythology, Tu Matauenga (also called Tu, Maru (Maori) and Ku (Hawaii)) is the god of war, envy and hatred who devoured his children and fought with the gods (particularly Tawhiri). He invaded heaven with an army of demons, but was defeated. He taught Tawhaki the arts of war, weaponry and chanting spells that paralyze his enemies. Generals pray to Tu Matauenga with a specific karakia (a kind of hymn) so that he may join on their side.

In Hawai'i, Ku was offered human sacrifices. These might be people who had broken a kapu, or low class people who were killed and placed on the altar to please the god of war. Human sacrifices were offered in New Zealand too, where the priest tore out the heart of the victim and offered it, or perhaps ate it himself.

In New Zealand, a boy was dedicated either as a farmer to Rongo, or as a warrior to Tu.

In planting traditions, Ku was the patron of hardwood trees, from which, among other things, agricultural tools were made.

He created Tiki, the first man.