Zhenwu

Xuanwu or Xuandi, also known as Zhenwu or Zhenwu Dadi, is a deity in Chinese religion and one of the higher-ranking deities in Taoism. He is identified as the god of the north, associated with water, winter, and the Black Tortoise — one of the Four Symbols of the Chinese constellations. He is particularly revered by practitioners of martial arts and as a protective deity against evil and disease.