Nu Kua

Nu Kua, Chinese creator-naga, uses the toes of the cosmic tortoise for the 4 cardinal directions. These became four animals: To the North, ruling over winter, is a Black Tortoise referred to as The Black Warrior. It represents the yin principle and the element, Water. (The Blue Dragon she established in the east to control spring. A White Tiger in the west was given control over autumn, and the Red Bird in the south was given control over summer. A Gold Dragon guarded the sun, and the moon was under the protection of a special White Deity.) http://www.khandro.net/animal_tortoise.htm