Asmodeus is the personification of Lust in greater Christian demonology. His name may be a derivation of, or etymologically related to, the Zoroastrian demon Aeshma. His depictions vary widely in various religious texts, both apocryphal and canonical; in some he is straight-up evil, but more often he is illustrated as being fairly comical and not especially mean-spirited or threatening.
Asmodeus is one of the primary demons that was tricked in to helping King Solomon build the temple of Jerusalem. In one extremely unusual origin myth, he is actually the son of Biblical patriarch David and a succubus.
In the Book of Tobit, a scripture which is canonical in Eastern Orthodoxy, he makes one of his more hostile and violent appearances. He is so in love with Sarah, future wife of Tobias, that he severely impeded all of her previous attempts to marry and engage in sex by killing her suitors; he, of course, is eventually thwarted and Sarah and Tobias happily marry.
As a demon of the Goetia, he pretends to be somebody else when first summoned, but when confronted with his true name he will begin to co-operate with the summoner. He has a wide array of powers and can teach the summoner on many subjects, including wood-working and handicrafts. He can also render people invincible so long as they remain in contract with him. As a demon of lust, he is expectedly fond of seducing women.