Venin are seen in various clothes; wearing blue or purple floor-length robes and holding a long misshapen cane - as well as in red fighting leathers. They are characterized by the “rivers of red veins fanning in every direction” around their red soulless eyes.
Depending on their rank their appearance can vary.

Sebastian looks like a man in his late 20s, a man in prime. Muscle clad and a handsome face if not for the soulless red eyes and veins on his face emanating his powers. 