Judaism believes that the satan (literally, “one who causes to turn [astray]”) is created by G-d and totally subservient and yet is tasked with a mission to make man stray. He in fact wants man to overcome for in the end he too wants G-d’s will to be fulfilled. An analogy is given that he passes the buck to someone who understands less clearly about G-d and His will. And in turn that (angel, being, etc) passes it to another (4-levels removed...ask your local kabbalist—but not Madonna’s) until the one holding the stick is on such a low level that he doesn’t understand at all that the original task came from G-d...and this emissary really does want to cause man to stray just for the sake of it. Anyway...it’s how we resolve the existence of a satan yet maintain that there is nothing (not even ‘evil’) that isn’t completely of, by, and subservient to G-d.
That’s it exactly. HaSatan is merely an angel of G-d doing his designated jobs. The notion that he is an independent principal of evil at war with G-d is sheer unadulterated dualism and a denial of true Monotheism.