Vilgax is an intergalactic alien warlord and conqueror, a Chimera Sui Generis who serves as Ben's archenemy, and the main antagonist of the franchise, having appeared multiple times in every series. Ben considers him as one of the most dangerous villains he has faced.
Vilgax is a humanoid creature with a face resembling that of an octopus. He has tentacles dangling in the front of his face, like a beard. His skin is pale green with yellowish spots on his face and tentacles. He lacks any sort of visible ears or nose. He has red eyes.
In the Original Series he wore a black and red-brownish armored suit and gloves. His armor was spiked at the shoulder and arm pads. He had green sacs on the sides of his head. His mouth was attached to the sacs by a respirator.
In Ben 10: Alien Force and Ben 10: Ultimate Alien , Vilgax had healed from his injuries in the first episode of the Original Series. He no longer had red-brownish armor, a mask, or green cheek sacs. He wore a red and blue armor. He had a belt which was attached to the raygun pocket. He wore dark blue stockings with metallic squares. He had the Ruby Ray of Rouleau on his right hand, and the Shield of Seagle on his left arm. He now had just five tentacles, all on the front of his face, and his eyes were larger. He also had a metallic plate replacing the green sac on his head.
In Ben 10: Omniverse Vilgax no longer possesses the Ruby Ray of Rouleau or Shield of Seagle. He has regained his original green cheek sacs and now has dirty teeth. Additionally, two of his face tentacles now end with a spiky-looking shape resembling actual squid tentacles. His armor is similar to his Original Series, with the exception being that the cylinders on his arms are now gold in color. He wears black clothes underneath his armor along with black stockings. Moreover, he now has fingerless gloves and wears a headpiece similar to his shoulder pads.
