Scars of Faerûn
Cyric, whose titles includ The Lord of Three Crowns, The Mad God, and The Prince of Lies is the monomaniacal deity of strife and lies with an immense following, though after he murdered Mystra and caused the Spellplague, his faith diminished somewhat.
He is petty and self-centered and enjoys misleading individuals of all inclinations so that they perform acts that ruin their lives. Cyric is closely associated with the essence of murder, conflict, lies, intrigue, and illusions.
He is recognized in Faerûn by his symbol, a white jawless skull on a black or purple sunburst.