Which Taoist deity is the ruler of the North Star?

The Taoist deity regarded as the ruler of the North Star is the Ziwei Emperor.

The Ziwei Emperor is also known as the Great Emperor of the North Star and the Beiji Emperor. In Taoist cosmology, he is one of the Four Sovereigns, a group of high-ranking celestial deities below the Three Pure Ones and associated with the administration of the universe.

Ziwei Emperor’s celestial office is broader than simply presiding over one star. He is said to reside at the center of Heaven, command the deities of the constellations, mountains, and rivers, and oversee natural phenomena such as the seasons and weather. His heavenly rulership also made him a religious counterpart to the emperor on Earth.

The North Star in this context is commonly associated with Polaris, but the deity should not be confused with Xuanwu, the northern protector associated with the Black Tortoise, or with the Jade Emperor, the supreme heavenly ruler in many popular accounts. “Ziwei” also appears in the name of the Purple Forbidden enclosure, a major celestial region in Chinese astronomy and astrology.