He is simply a liar, telling people what they want to hear. His classics lies today are; - Have fun, what's a little sex between friends. - Take whatever you can get, they'd take it from you if they could. - It's just a little sin, God doesn't care about it. Beside you can just insincerely repent later and He will forgive you. The lies go on and on. Always just the encouragement that a little evil is no big thing, and that doing good doesn't pay off. His message is so prevalent now, that in many ways, his lies have become the philosophy of our youngest generation.
The Satan tempts people to sin, then prosecutes them in the Heavenly Court, and if convicted, serves also as executioner (Baba Batra 16a). He does all that under a charter from God, and sometimes under God's orders. Of course the Satan does other things too. E.g., the Satan appeared as Isaac to Sarah after the Binding of Isaac, and caused Sarah's death (Midrash Tankhuma Vayera Ch. 23). His name is not Satan - his job title is the Satan. For the most part he is the prosecutor in Heavenly court.
Satan is Father of Lies. It makes that which is wrong seem good and/or desireable (temptation). It has many agents on this site as well so beware. They do its bidding here, some unknowingly but some deliberately.