Hex is one of the recurring antagonists in the original Ben 10 series. But unlike most villains in the original series, while Hex is an enemy towards Ben Tennyson, Hex is more of an enemy towards Lucky Girl (Gwen Tennyson). He is also Charmcaster's uncle.
He is voiced by Khary Payton, who also voiced Cyborg in the Injustice series, and in other media.