Maru is a Maori war god, especially well known in southern New Zealand, where he replaces Tūmatauenga, the war god of the rest of New Zealand.
Maru is the son of Rangihore (god of rocks and stones) and the grandson of Māui. Maru's image was brought to New Zealand by Haungaroa.
He was also known as the god of wai maori (fresh water) like streams and rivers.
References
Maru (mythology) Wikipedia(Text) CC BY-SA