Season 1, Episode 21
Air date December 12, 2010
Written by Rob Hoegee
Directed by Rick Morales
Episode guide
Images | Quotes | Transcript

"Payback" is the 21st episode and season finale of season one of Generator Rex. It is the 21st episode of the overall series. It debuted on December 12, 2010.


Van Kleiss decides to go after Rex in order to reclaim the nanites that were stolen from him. In doing so, he gains the ability to turn people into EVOs and proceeds with his plan to destroy Providence once and for all.


Van Kleiss has lost his nature-controlling powers over Abysus at Rex's hands... and now he wants revenge. His goal is to destroy Providence from the inside out and absorb all of Rex's nanites to make himself stronger than ever before.

He succeeds in draining Rex of all his nanites except for the large, unusual nanite that Dr. Gabriel Rylander had injected into him in "Dark Passage", and which previously saved Rex's life in "The Swarm". However, Rex's nanites have an opposite effect on Van Kleiss; as Rex was able to cure EVOs, Van Kleiss is now able to create them. He demonstrates this with Captain Calan, turning him into a stone spider-like EVO.

Rex deactivates bombs

Rex deactivates Van Kleiss' bombs in Providence.

As a last resort to stop Van Kleiss from destroying Providence, Rex intends to refill himself with nanites from the Purgatory base, which activates Rylander's Omega-1 Nanite. Rex regains his original powers as well as new machines, and uses them to stop Van Kleiss.

In the meantime, Doctor Holiday takes down Skalamander with some help from her sister, while White Knight deals with Biowulf and a technopathic EVO using a powerful electromagnet that prevents himself from being infected with stray nanites. Van Kleiss manages to escape on his EVO whale blimp, while the EVOs left behind are arrested by Providence agents. At this time, Breach has completed setting up bombs all over Providence Headquarters. When Rex finds out, he is able to link with the entire base and shut down all installed bombs.

Later, Rex cures Captain Calan from his EVO form. White Knight, in his nanite-free battle suit, arrives in person and says that this was not their finest hour, as the Keep and Providence Headquarters will need extensive repairs. Rex assures them all, that though Van Kleiss may be back and more powerful than ever before, so is he, and that the war against humans and EVOs is not over yet.


Voice Actor Role(s)
Daryl Sabara Rex
Wally Kurth Agent Six
Captain Calan
Fred Savage Noah
Grey DeLisle Dr. Holiday
John DiMaggio Bobo Haha
J. K. Simmons White Knight
Troy Baker Van Kleiss
Providence tech
Non-speaking role(s)
I-Bol (debut)


  • When Skalamander shoots crystals at the trees, the crystals on his arm disappear.


  • The Generator Rex theme song "Revolution" is heard for the first time outside of the title sequence.
  • The Omega-1 Nanite is activated for the first time and is identified, at first, as a Control Nanite by Dr. Holiday. As a result, Rex gains a new machine called the Blast Caster that can lengthen and generate electric shocks.
  • A Providence agent is revealed to be a spy for Van Kleiss.
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