Eon is a time-travelling villain and the archenemy of Professor Paradox. He is the main antagonist in Ben 10: Race Against Time. He differs in the different series he appears in; in Ben 10: Race Against Time, he appears as a humanoid alien from the planet Chronia, in Ben 10: Ultimate Alien he looks like Ben 10,000 and in Ben 10: Omniverse he is a human with time-based powers.
Eon was once a member of the Chronian race whose home planet was banished out of time as a result of his people's folly with their powers. After escaping this fate and landing on Earth, he seeks a rare object known as the Hands of Armageddon that can free his people and start a war against Earth. He was, however, taken into custody by the Plumbers and was frozen in a cryogenic cell for 200 years before finally thawing out and aging his guardian to near death. He then recruits ape-like henchmen to help him reach the Hands.
Ben 10: Race Against Time
He first appears when he starts blasting energy at objects in the town, Bellwood. Later, when Heatblast appears and then the police appear. Heatblast stops Eon's Servants and later seemingly defeats Eon.
Later, Eon appears at a clock tower. When Eon gets a headache, one of his servants try to help him but he kills it with an energy blast revealing its face. Eon informs the rest of his servants to "let him die", as they are here to serve him, not each other and threatens them to put them back in their cold cages. Eon views his home planet and the ships of the fleet of his race who are trapped outside of time and space. He says that nothing shall thwart him once Ben Tennyson is dead.
Eon appears in an image that Gwen Tennyson has taken. When Max Tennyson appears he tells Ben and Gwen about Eon. Later, Ben, Gwen and Max Tennyson meet up with a plumber who was in charge of Eon, Constantine Jacobs that was aged by Eon to the point that he was old in the blink of an eye. After the plumber finishes explaining about Eon, he dies.
Eon later appears, trying to activate the Hands of Armageddon but he's to old to do so. When Eon sees Ben Tennyson, he malfunctions his Omnitrix. Ben Tennyson tries to get away but Eon gets him cornered. Eon is stopped by an old plumber.
Later, Eon appears at the hall of Ben's school. Ben fights Eon as Diamondhead. Eon reminds Ben that when an alarm sounds, the entire school gathers to the hall. Eon teleports away and Ben hides.
Eon appears with Ben, Gwen and Max, chained, after being kidnapped by his servants. Eon tells Ben, Gwen and Max about his race, planet, the Hands of Armageddon, the Omnitrix and he also tells Ben that he is him. Eon turns Ben into a younger version of himself and teleports away as two cannot exist in one world.
Later, the real Eon appears and stops time, except from Ben. When he throws Ben, Ben turns into Wildmutt and fights him. Eon is whacked into the Hands of Armageddon by Wildmutt using frozen Gwen, defeating Eon.
In Ben 10,000 Returns, it is revealed that Race Against Time was just an alternate timeline. As it turns out, Eon survived the battle against the Ben of that timeline and had been hunting down alternate versions of Ben, stripping them of their powers and placing them under his control.He is first seen battling Ben 10,000 at his headquarters. His servants join in when Eon points out that he didn't come alone like Ben 10,000 anticipated. Ben 10,000 traps Eon's Servants in Diamondhead crystals and blasts Eon away with Clockwork's time ray, seemingly destroying him in the process. However, Professor Paradox arrives and reveals that Eon actually tricked Ben 10,000 into sending him to the Main Timeline where another version of the Hands of Armageddon can be found. The duo also travel to the Main Timeline and encounter present-day versions of Ben Gwen and Kevin, who already found the Hands before Eon does. After explaining cross times to the gang, the team carry the Hands into the desert where both Bens begin destroying it using Way Big and Clockwork respectively. Unfortunately, this turned out to be a ruse planted by Eon to get them to open a bridge for him and his minions to pass through. During the battle, Eon destroys Way Big Swampfire and Ultimate Swampfire by aging them to dust with his powers. Gwen then uses a spell to freeze time where it is revealed that Eon's servants are all alternate versions of Ben. Eon also unmasks himself showing an identical face to that of Ben 10,000's, revealing his reason for hunting down the alternate versions of Ben so that he can be the one and only Ben in the space-time continuum. Just then, the real Ben uses Jetray to destroy the Hands and both Eon and his servants vanish much to Eon's dismay. According to Professor Paradox, the alternate versions of Ben are now restored to their respective timelines and the Hands of Armegeddon is destroyed in not just one timeline but in all of them.
Eon reappears in the episode Ben Again, having been trapped in the main timeline by Professor Paradox. Wanting the freedom to travel multi-dimensional once more, he tries to lure the time-walker into showing up by switching 16 year-old Ben's mind with that of his 11 year-old self. Knowing that Paradox wouldn't show up in the present (as the 11 year-old Ben doesn't know him), he goes to 11 year-old Ben's time zone and manages to capture Paradox taking him to his own dimension for interrogation. Eon demands the possession of the Chrono-navigator, but Paradox claims he doesn't have it. Aware of the time-walker's inability to lie, Eon discovers that his robotic hand (which he sliced off of Paradox during their battle) was his Chrono-navigator and manages to retrieve from 11 year-old Ben in the present day. Eon decides to use it to control all timelines, but misuse over the device angers him to the point where he decides to destroy all reality instead. Paradox urges both Bens to use their parallel versions of Clockwork to banish Eon back into his own dimension while he is freed by both 11 and 16 year-old versions of Gwen. Paradox reunites with his Chrono-navigator and undoes the damages Eon caused in the episode.
In And Then There Were None, Eon joins forces with Vilgax to create an army of evil versions of Ben (which is made up of Albedo, Bad Ben, Nega Ben, Mad Ben and Benzarro). Together, they travel to the No Watch Timeline to target No Watch Ben, who is the only Ben in the universe to have never received an Omnitrix. Luckily, Ben Prime and Professor Paradox also travel there to rescue No Watch Ben and bring him to Los Soledad where Professor Paradox explains cross-times to No Watch Ben. After Paradox leaves to investigate, Eon shows up and tries to kill No Watch Ben. To make matters worse, Vilgax and the evil Bens find them and surround them. Just then, Professor Paradox manages to gather his own army of good Bens: Ben 10,000; Ben 23 and Gwen 10. As both armies struggle in battle, Vilgax betrays Eon and uses a Chronosapien Time Bomb to destroy all timelines in reality with the exception of the No Watch Timeline, thus wiping out every Ben Tennyson who ever had an Omnitrix including Eon himself.
In And Then There Was Ben, Eon appears in a past battle against Ben 23 attempting to recruit him. Unbeknownst to him, Professor Paradox Gwen 10 and No Watch Ben (who acquired the Omnitrix from Ben Prime before the latter's death) were also in Dimension 23. The three manage to secretly help Ben 23 without being caught by Eon, causing him to leave. Later, Eon and the other alternate versions of Ben were resurrected when No Watch Ben used Clockwork to restore the timelines that Vilgax destroyed earlier. Eon angrily attacks Vilgax for his betrayal, but was stopped by Ben 10,000 as Atomic-X. Eon and the evil Bens were then sent back to their respective timelines by Clockwork.
- Eon's plot is Ben 10,000 Returns is similar to the DC comics super villain Grog. However, unlike Grog who murdered the alternative versions of the hero, Eon simply placed them under his control.
- The relationship between Eon and Professor Paradox is similar to the relationship between The Master and Doctor Who from the television series Doctor Who:
- Both are time travelers
- Both are archenemies
- Both travel through dimensions.