Dimension 1 (John Smith 10)
Vilgax first appears in his ship trying to get the Omnitrix. Just like the canon series, his ship is damaged and himself injured. He sends Techadon robots and Bounty Hunters after John. He doesn't make a physical appearance until Rob Lucci brings John to him. He causes the Omnitrix to malfunction, it shifting John through his aliens. Gwen and Kevin help fight Vilgax, and they escape, Vilgax's ship exploding.
Vilgax returns later, his attack on Earth revealing John's identity to the world. He challenges John to Conqueror's Challenge, and awaits John. The two battle, Vilgax's enhanced strength allowed him to pound through all of John's aliens, eventually breaking Chromastone. After claiming victory, Julie throws something at him, him going to kill her. John as Diamondhead protects her, and defeats Vilgax. Vilgax is forced to leave.
Vilgax, in exile, has built up a robot empire on the planet Turrawuste. John goes to the planet to find Kai and Yenal, and they attack the base to be able to escape. John and Vilgax battle again, and John was able to defeat him. The gang then leaves the planet.
Vilgax remains on Turrawuste, when he's approached by an Esoterica, being offered the power of the Diagon. Vilgax goes to Earth to obtain Diagon's heart and Ascalon. Julie as an Esoterica then tells him to break the seal of Diagon, which he does. Vilgax is sucked into Diagon's dimension, and is merged with a Lucubra to gain more power. He serves as Diagon's servant, while he waits for Psyphon to arrive with the energy drainer. However, Vilgax is defeated by Brago and Sir George, as Psyphon is defeated.
Vilgax briefly returns later, having gone conquering worlds, gaining new powers and equipment. He wields the Petropian Back-up Crystal, responsible for destroying Petropia and is the key to reviving Petropia. John battles Vilgax to obtain the crystal, so he can restore Petropia in time. He defeats Vilgax and gets the crystal, reviving Petropia.
In the dimension of 15, Vilgax is the main villain of a crossover. He takes an Ultimate and Infinite form, and is only barely defeated by John and working together. It is uncertain if it's John's or 's Vilgax, as Vilgax knows John.
Vilgax doesn't return until the end of Phantom Watch. He was offered a position in the New Chess Pieces, but he declines. Zombozo is sent to kill him, but instead forms an alliance with him and Albedo. After John destroys Phantom's army, the three attacked Phantom, Vilgax taking the Warmatrix for himself. He battles John with his new transforming powers, and drives John off with Albedo's help.
Vilgax connects an army of Bioid robots to the Warmatrix, able to transform them. John battles Vilgax, Julie and Sunder battle the Warmatrix drones, while Gwen and Kevin battle the Bioids. Vilgax, driven into a corner, turns into Diagoneir, where Diagon takes control of him. John forces the Warmatrix to time out, Vilgax down. John takes the Warmatrix away, and Vilgax away.
Vilgax is recruited by Prometheus, who offers him ultimate power in exchange for taking down the Greek Gods. They go to Mt. Olympus, as Vilgax claims the Promethium, gaining the power of the gods. John and Elektra eventually make it there and battle him, John barely able to be even with him. Elektra shoots an arrow, destroying the Promethium. John then sends Vilgax flying into space.
In the dimension of Ben 10, Vilgax is drawn to Earth to release and obtain the power of Gaia. He uses his energy draining machine to absorb Gaia into himself. However, Gaia takes control of Vilgax, and John has to force Gaia out. Ben then sends Vilgax flying into space.
Sometime after the events of Mt. Olympus, the Plumbers successfully captured Vilgax, something John was surprised at. John agrees to take Vilgax to Incarcecon, when they are attacked by the Black Hawks, who were hired to kill Vilgax. Though reluctant, John and Vilgax work together and help drive them off. However, Vilgax escapes while John finishes the Black Hawks off.
- The Omnitrix (first appearance)
- Vengeance of Vilgax Part 1 (John Smith 10)
- Vengeance of Vilgax Part 2 (John Smith 10)
- The Widening Gyre (John Smith 10)
- A Knight to Remember (John Smith 10)
- The Beginning of the End (John Smith 10) (merged with Lucubra)
- The Ultimate Enemy Part 1 (John Smith 10) (merged with Lucubra)
- The Ultimate Enemy Part 2 (John Smith 10) (merged with Lucubra)
- The Secret of Chromastone (John Smith 10) (first re-appearance)
- Incarcecon Breakout, Part 1 (first re-appearance) (alternate dimension?)
- Incarcecon Breakout, Part 2 (alternate dimension?)
- Ghost of a Battle (illusion)
- Unlimited Power (John Smith 10) (first re-appearance)
- The Final Battle Part 1 (John Smith 10)
- The Final Battle Part 2 (John Smith 10)
- Vilgax Goes Screech
- The Conqueror (John Smith 10)
- Battle of Vilgaxia Part 1
- Battle of Vilgaxia Part 2
- Two of Everything
- Last Chance
- Fated Battle
- Only Human (John Smith 10) (cameo)
Dimension 10 (Ben 10)
This version of Vilgax is based in the dimension of the canon Ben 10 series.
Dimension 2 (Ryder 10)
Vilgax's beginning is the same as the canon series and John Smith 10, when he attacks the ship transporting the Omnitrix, and is mortally wounded in the process. After a few of his robots fail to get the Omnitrix, he hires Khyber, the galaxy's greatest hunter, to retrieve the Omnitrix. Meanwhile, Dr. Psychobos is helping Vilgax heal, giving him cybernetic enhancements.
Once Vilgax is healed, he goes after Ryder himself, able to defeat him and his friends. After taking Ryder up to his ship, Ryder escapes, the ship blowing up in the process. While thought dead, he is revealed to be alive when he speaks to Rojo who had merged with his robot. He and Psychobos attack the Mt. Rushmore Plumber base in an attempt to get Ryder and the Omnitrix. Vilgax and Ryder are sucked into the Null Void, and Vilgax chases Ryder throughout it. Ryder manages to escape the Null Void, leaving Vilgax trapped.
- Rev it Up
- Hit the Road
- Hunted (Ryder 10)
- Grudge Match (Ryder 10)
- The Alliance (Ryder 10) (vision only)
- The Color of Monkey (Ryder 10)
- Back With a Vengeance (Ryder 10)
- Secret of the Omnitrix (Ryder 10)
Vilgax appears in Dimension 0, wanting the Omnitrix which has fallen to the Earth. He sends GIR and Psyphon to get it, but goes to get after Psyphon fails, as GIR destroys everything with the Omnitrix. GIR defeats Vilgax, trampling him with pigs.