Isis is the mover and shaker of the Egyptian pantheon. She is one of the main antagonists and protagonists.
Early on, she poisons Ra, and while Ra is sick, she lets Ra know that she can cure him, but only if Ra gives her his true name. This means that Isis holds power over Ra, which is a handy thing.
Isis is an important character in the cycle of stories about her husband Osiris and his rivalry with their brother Set. Isis is responsible for finding all the pieces of Osiris and putting him back together long enough for her to engage his affections and conceive Horus. Isis and Horus hide from Set until Horus is old enough to challenge Set for the leadership of Egypt. We’ll come back to that in another entry.
Isis governs the province of magic, and she has longevity, being worshiped into Greco-Roman times. She is a mistress of manipulation, representing the mother and the spouse, literally the great woman behind every man.