In Bhagavad-gita the Lord says that whenever one sees an extraordinary power, he should conclude that a specific partial representation of the Supreme Personality of Godhead is present. There are innumerable such personalities, but not all of them are direct visnu-tattva plenary expansions of the Lord. Many living entities are classified among the sakti-tattvas. Such incarnations, empowered for specific purposes, are known as saktyavesa-avataras. King Prthu was such a saktyavesa-avatara of the Lord. Similarly, Arci, King Prthus wife, was a saktyavesa-avatara of the goddess of fortune.