Noun
an angel believed to have special affection for a particular individual
Source: WordNetIf the transmigration of a soul takes place into a rational being, it simply becomes the soul of that body. But if the soul migrates into a brute beast, it follows the body outside, as a guardian spirit follows a man. For there could never be a rational soul in an irrational being. Sallust
One must have to wait till the evening of one's life time to know what gratitude to pay to one's guardian spirit. Nigerian Proverb
The Nez Perce believed in spirits called weyekins (Wie-a-kins) which would, they thought, offer "a link to the invisible world of spiritual power". citation The weyekin would protect one from harm and become a personal guardian spirit. Source: Internet
Prior to being born, the urvan (soul) of an individual is still united with its fravashi (guardian spirit), which has existed since Mazda created the universe. Source: Internet