The Dark Alliance are the main antagonists of Season 2 of Ben 10: Omniverse Traveler. They are a team of three of Ben's most dangerous foes.
Vilgax is one of the main antagonists of Ben 10 as a whole. He seeks to take control of Ben's Omnitrix and gain limitless power. He is the founder of this team. He claimed to be planning on creating three ultimatrixes: One for him and one for each ally, but in truth he planned on absorbing them and their powers.
Aggregor is the former second in command, turned leader of the team. He agreed to assist vilgax in exchange for the unlimited power that came with the Omnitrix. However, in truth, he realized that Vilgax was going to absorb him, and began to develop his own plans...
Zyrassig is a former Highbreed Commander, who was celebrated as a paragon of their ideals. However, in his eye, Ben 10's genetic repair of the species ruined them. Now, he seeks revenge on Ben 10 for corrupting his people. He joined the organization, Oblivious to Vilgax's treacherous tendencies, and functions as the asisstant. He seeks the omnitrix to turn his people pure again, ignorant of the fact that this would kill them.
- In A Cosmic Beginning: Part 1, Zyrassig begins a plot to turn the Highbreed pure again. He builds a modified Highbreed Pulse Generator, and begins taking it to Augstaka, with Ben 10 and his allies giving chase.
- In A Cosmic Beginning: Part 2, he activates the device. It purifies him for a moment, only for Ben, as Upgrade, to shut it down, reversing what effects it did have. In a rage, he tries to kill Ben, but Ben turns into Atomix, and defeats him. Vilgax is shown teleporting Aggregor and Zyrassig in from the corners of the universe as they begin to scheme.
- In Attack on Azmuth, Ben gets an emergency alert from Azmuth that Aggregor had broken into his lab. The heroes ran in to stop aggregor. Rook tussled with aggregor, but was defeated. Kevin jumped in and challenged Aggregor, but was nearly killed. Aggregor snatches Ascalon, and leaves.
- In Junkyard Brawl, Ben is visiting Aul-Turrhen when Vilgax arrives. He is looking for a Aul-Turrian Spinmotor. Vilgax battles Rook, Kevin, and Ben. After a long fight, they are defeated. Ben's Omnitrix powers on just as Vilgax is about to shred him. He activates it, hoping for something good, but gets Jurryrig. In a last ditch effort, Jurryrig builds a huge robot from the junk they're surrounded with. After a battle, Vilgax is left heavily injured and buried in junk. Rook quickly aapprehends him, only for Aggregor to arrive and shock Rook off of him. Aggregor and Vilgax leave with equipment they need, as Aggregor begins asissting Vilgax in getting back to full power.
- In Roots of Evil, Ben and his crew arrive at the Plumber Base after reports of hundreds of plumbers going missing as roots appear from every nook and cranny of the Plumber Base. After an investigation they discover Zyrassig, who has captured the plumbers and has them ensnared. They defeat him after a battle, but he gets away.
- In The Omniwar, Ben hears reports of Zyrassig in the area, and chases him to a mysterious enormous spaceship. There, Ben and his teammates find themselves hunted by Zyrassig, Aggregor, and Vilgax. They get into skirmishes with the heroes. The heroes quickly realize that fighting is not working, so they flee as much as possible. However, eventually they are cornered. Vilgax binds them, and uses the device to remove the complete Omnitrix. He then places it on his hand, revealing that he had no intentions of giving the other two their Omnitrixes, and immediately binds them with cables. He reveals that he was planning on absorbing Aggregor all along, and hooks aggregor up to the machine. Aggregor seems strangely calm, however. Vilgax sits in a chair, waiting for the power of aggregor to flow through him. However, the machine instead begins absorbing vilgax. When Vilgax acts outraged and confused, Aggregor revealed that he knew Vilgax's tendency for backstabbing, so he began wondering where the betrayal was coming from. He searched around and found the extractor, so he tampered with it to make it so it absorbed the user into the target instead. He then transforms into Aggregax after vilgax finishes dissolving.
- In Vengeance of Aggregax: Part 1, Aggregax charges at Ben, only for Kevin to absorb metal and jump in the way. He is badly injured, however. Gwen creates a magic shield, but Aggregax reveals a secret: he absorbed the omnitrix and Vilgax, so he then turns his arms into heatblast mode and pulverises Gwen's shields. Rook realizes it is a losing battle, so the four heroes begin to flee. They avoid Aggregax attack after Aggregax attack, but soon become lost in the maze. Gwen creates a doppelganger of them crawling through the vents, while they turn invisible and sneak away. It nearly works, but when they are near the spaceship, Aggregax catches them. They just barely make it out in time.
- In Vengeance of Aggregax: Part 2, Ben and his team fly to Azmuth's lab as fast as possible, while being chased by Aggregax. They make it to Azmuth's lab, and Azmuth reveals that he made an improved nemetrix. Kevin, Gwen, and Rook hold off Aggregax long enough for Ben to get the Ultimatrix. He goes Ultimate Four Arms, and defeats Aggregax, sending him flying outside. However, Aggregax turns as tall as a skyscraper, revealing that he was waiting to be somewhere he could unleash his tokustar powers. Ben's Ultimatrix times out, but he goes Ultimate Chromastone and absorbs a cosmic ray, magnifying it and sending it flying back at Aggregax. The two keep fighting, but Ben wins. Ben then drains the energy out of Aggregax, leaving nothing but a depowered Aggregor. Aggregor and Zyrassig are then apprehended. Azmuth then says, "Good thing he didn't realize there was celestialsapien energy in this. Otherwise we'd really be doomed." before having Ben transfer the energy into a container.