A member of the alien Chimera Sui Generis species from the planet Vilgaxia, Vilgax is a despotic warlord with designs on galactic domination. He is a powerfully-built humanoid with sharp claws on each hand, and is possessed of an astonishing degree of superhuman strength and fortitude; despite this, he can move with an agility which would put the finest human gymnast to shame. He can also transform his arms into long and flexible tentacles to give him greater reach, and has demonstrated the ability to fire immensely powerful beams of concussive energy from his eyes.
The Original Series Vilgax was also capable of flight under his own power, both in an atmosphere and at incalculable speed through the void of space.
Both versions are widely feared and reviled throughout the known galaxy, and Vilgax must therefore utilise the services of robotic drones to enact his schemes.
Vilgax spends much of his time in pursuit of the alien artefact known as the Omnitrix, as he sees this as being the key to unlocking his plans for ultimate domination of the cosmos. As one might expect, this has led him into many and frequent confrontations with child hero Ben Tennyson, and he has developed a deep-seated hatred for the boy and his family as a result.