Ben Tennyson (Classic)/Omniverse

A few months after the events of Ultimate Alien, Ben was left to be a solo hero after Gwen Tennyson and Kevin Levin left for college in The More Things Change: Part 1. However, Max had other plans. He teamed Ben up with a Plumber rookie named Rook Blonko. Ben did not want to have a partner and tried refusing Rook, but it was in vain. Setting their differences aside, the two soon learned to work as a team and look out for each other.
In The More Things Change: Part 2, Ben along with Rook, investigated Undertown. They met Psyphon, who revealed that he had started a gang. Ben battled and defeated Buglizard as Shocksquatch with the help of Rook, and the Plumbers arrested Psyphon and his gang members.
In A Jolt From the Past, Ben discovered that a villain named Fistrick and his gang were illegally keeping the Nosedeenians. Ben and Rook freed the Nosedeenians, and the Plumbers arrested Fistrick and his gang. Ben also unlocked and transformed into Gravattack.
In It Was Them, Ben was attacked by Slamworm, which was the work of Khyber. His suspicion arose over these attacks. Later, he and Rook went to arrest Animo who had escaped Plumber Headquarters. At Animo's hideout, Ben was once again attacked, this time by Mucilator. Eventually, Ben and Rook defeated Mucilator and arrest Animo. Ben unlocked Crashhopper.
In So Long, and Thanks for All the Smoothies, Ben and Rook checked out a mysterious ghost ship. which was revealed to be a Contumelia Ship. Later on, after meeting old enemies, Ben had to transform into Alien X to save the universe from the Annihilarrgh, a doomsday device created by the Contumelia to destroy universes. When Alien X transformed back into Ben, he gained a green and white jacket that had a hoodie, and a number 10 logo.
In Trouble Helix, Ben transformed into Chromastone and Cannonbolt to help Blukic and Driba test a weapon.
In Hot Stretch, Ben encountered Ester, a Kraaho, who stole a Nuclear Fusion Device. He met Seebik, the leader of the Kraaho. Eventually, Ben developed a crush on Ester and together they put an end to Seebik's evil heist. Seebik was defeated and Ester became the new leader of the Kraaho.
In Have I Got a Deal for You, Ben met Blarney T. Hokestar, a dealer and Pax, an alien right activist who claimed Hokestar was illegally keeping a Screegit. This was proven true and, since the Screegit reacted with nitrogen gas, it created trouble. However, it was subsequently defeated by Ben and Hokestar. Then Solid Plugg, assistant of Hokestar, and Pax were arrested.
In Of Predators and Prey: Part 1 Ben and Rook broke up their partnership because of a fight, and Ben's Plumber's badge is destroyed. Ben was then attacked by Khyber and his pet. He transformed into Crashhopper, but Khyber's pet transformed into Mucilator and fell on Crashhopper, who transforms into Armodrillo and throws Mucilator.
Mucilator then transformed into Slamworm and went underground, attacking Armodrillo. Armodrillo transformed into Heatblast and chased after Khyber but was met with a surprise attack by Crabdozer. Then, Khyber introduced himself as the 'greatest huntsman in the galaxy'. However, Ben just mocked him. Heatblast tried to transform into Humungousaur but transformed into a new alien named Ball Weevil. At first, Ben didn't know how to use Ball Weevil's powers, but then spat a ball and rolled around uncontrollably before seeing that the ball could explode. Crabdozer countered this by transforming into Terroranchula.
Ball Weevil fled, but Khyber defeated him by redirecting one of his attacks. The Omnitrix timed out, and Ben fell down unconscious. Khyber then picked him up and started gloating.
In Of Predators and Prey: Part 2, while being imprisoned in Khyber's Ship, Ben eventually discovered that Malware was involved in the creation of the Nemetrix from Khyber, the device that allowed Khyber's pet to transform into predators of aliens, and that Dr. Psychobos, using a corrupted blueprint of the Omnitrix retrieved by Malware, created the Nemetrix. Dr. Psychobos hired Khyber to collect predator samples for the Nemetrix and they used Phil as a test subject. Rook then came to Ben's rescue, revealing that their argument was part of their plan to lure Khyber and that Ben's Plumber badge was not destroyed. They defeated Khyber and he crash landed. The wreckage of his ship was visited by Malware and Dr. Psychobos.
In Outbreak, Plumber Headquarters was attacked by Dr. Psychobos, who stole an Omnitrix component to perfect the Nemetrix. In the process, the now mutated Psyphon and his gang members caused chaos until they were defeated by Ben, Rook and a squadron of Plumbers. Blukic and Driba replaced the component stolen and, in this process, they unlocked new aliens. Ben also unlocked Kickin' Hawk as a result of scanning Liam.
In Many Happy Returns, Gwen and Kevin came to Bellwood to visit Ben. Ben defeated Looma Red Wind, a Tetramand to whom Kevin was engaged, but in this process, Ben accidentally got engaged to her.
In Gone Fishin', Magister Patelliday was kidnapped by Captain Kork and his Mechaneer while he fished with Max, Ben, and Rook. Max, Rook, and Ben infiltrated Kork's headquarters, rescued Magister Patelliday and arrested Kork.
In Blukic and Driba Go to Mr. Smoothy's, Ben and Rook were busy chasing after Trombipulor who was after ultimate power which was revealed to be peanuts. Blukic and Driba tried to go to Mr. Smoothy to buy a grasshopper smoothie. Ben also learned of the existence of a 23rd store of Mr. Smoothy.
In Malefactor, Khyber and his pet attacked Ben at a festival. Ben recognized Hypnotick's species and came to the conclusion that this was just a distraction. Ben reached the Proto-TRUK and found Malware stealing data from it. Malware escaped and Ben showed fear towards him in this episode.
In Bros in Space, Ben and Rook visited Revonnah, Rook's home planet. Rook introduced Ben to his family and his crush. Later, a Muroid attacked standing on two legs which was strange as they should walk on four legs. At night, Ben found out that there is a TV show about him. The next morning, the Revonnahganders were harvesting and Ben tried to help them. In the end, it was revealed that Fistrick was manipulating the Muroids so that he could steal Amber Ogia, the sacred food, crop and fuel of the Revonnahganders. He was defeated with the combined efforts of Ben and the Revonnahganders.
In Arrested Development, Ben and Rook fought the Computron's Minions and met Billy Billions. At first, Ben mistook him for a fan, but then it was revealed that he was controlling the robots. As it turned out, Billy had a rivalry with Ben when they were young, though it was one-sided. Amidst the rivalry, Billy fired a beam at Ben but since he was Diamondhead at that time, the beam was deflected and warped Billy to Dimension 12. Billy used a De-Ager Ray on Ben and Rook, transforming them into young versions of themselves. Eventually, Billy accidentally caused an invasion of the robots. The robots were stopped by Ben and Rook who managed to revert to their original ages. After that, Billy was arrested.
In Rules of Engagement, Julie and Ship helped Ben defeat Looma. Ben started going out with Ester. 
In Showdown: Part 1, the Faction infiltrated Galvan Prime and planned to humiliate and kill Azmuth. Azmuth teleported Ben and Rook to help him capture Zed and Dr. Psychobos. Khyber escaped with the Nemetrix. It was revealed that Malware was on Galvan B. At the end of the episode, Galvan B was destroyed with Malware being stronger than he was before.
In Showdown: Part 2, Ben, Rook, Azmuth, Gwen, Kevin, Max, Blukic, and Driba had a final showdown with Malware. Even Way Big was defeated by Malware. Ben then had a flashback of what happened when he was 11 and how he lost Feedback. He eventually regained Feedback by overcoming his trauma, and by absorbing the Helix's power, he defeated Malware once and for all.
In T.G.I.S., Ben teamed up with the Secret Saturdays to defeat Animo and V.V. Argost, developing a crush on Drew and becoming friends with Zak.
In Store 23, Ben discovered a new dimension with its own version of him, whom he tutored in how to be a hero.
In Vilgax Must Croak, Ben tried to escort Vilgax to Incarcecon, only for him to escape due to the Incurseans' intervention. 
thumb|Ben teaming up with his 11-year-old self
In Ben Again, while battling Eon, 11-year-old Ben's mind was switched with that of his 16-year-old self. As 16-year-old Ben, he found the clues laid down by the 16-year-old Ben who was inhabiting 11-year-old Ben's body. Both Bens got their bodies back and defeated Eon.
In Special Delivery, Ben had to deliver goods for Mr. Baumann as penance for wrecking his car. He quickly discovered that Psyphon was once again up to no good when he tried to steal a Dwarf Star. Ben unlocked Toepick and defeated Psyphon with the new transformation.
In Rad, Ben met Rad Dudesman and teamed up with him. Other episodes featuring his fight with the Incurseans culminated with Milleous' arrest and Attea's rise to power. In this arc, Ben also unlocked Astrodactyl and Bullfrag.
In Food Around the Corner, Ben helped a peace treaty to develop between the Lewodans and Appoplexians. 
In O Mother, Where Art Thou?, Ma Vreedle searched for her son and threatens to destroy the sun, but Ben and his allies stopped her. 
In Max's Monster, present-day Phil returned with a powerful transformation.
In Return to Forever, the Forever Knights attempted to destroy Undertown. 
Mud is Thicker Than Water reintroduced Ben's Lenopan cousin, Lucy, who helped uncover how Psyphon had been getting his hands on Plumber tech. 
OTTO Motives featured Ben, Kevin, and Rook battling a robot named Otto.
The other episodes in Season 4 featured Ben's fight with Albedo, culminating with Ben unlocking Atomix and Albedo being turned into an 11-year-old version of Ben.
In Something Zombozo This Way Comes, Ben fought Zombozo, his zombie clowns, and the Circus Freak Trio. Ben managed to defeat them, but not before into his fear of clowns returned. 
In Mystery, Incorporeal, Ben and Rook visited Gwen's college, Friedkin University, and defeated Michael Morningstar. As a reward for saving the day, Ben was granted an honorary degree, referring to himself as Dr. Tennyson, much to Gwen's chagrin. 
In Bengeance is Mine, Ben fought Vilgax's Squid Monsters, who wreaked havoc on Bellwood. He defeated them with the help of an ordinary plumber named Bill Gacks.
In An American Benwolf in London, Ben was rejoined with Kai Green, his former crush. With her help, he defeated the Forever Knights before they could get Excalibur. 
In Animo Crackers, Dr. Animo's future self went back in time to work with his present self. Chrono Spanner, a hero from the future, met up with Ben and, together, they defeated both Animos.
Other episodes in Season 5 featured Ben's fight with Zs'Skayr and his henchmen. Ben unlocked Whampire and destroyed Zs'Skayr, defeated his henchmen, and imprisoned the resurrected Vladat, Lord Transyl.
In And Then There Were None and And Then There Was Ben, Ben teamed up with his alternate timeline counterparts, including his future self to take down Vilgax and the evil Bens.
In Catfight, Ben went on a date with Ester. Eventually, Nyancy Chan intervened, but she was defeated and Ben resumed his date with Ester. 
In Collect This, Ben found out that there was a show about him, run by Hokestar, Solid Plugg, Simian, and Deefus. Eventually, the Earth was sold to Collectimus, who, at the end of the episode, traded it for Ben's shirts. 
In The Vengers, Captain Nemesis, Kangaroo Kommando, Billy Billions, and Mazuma formed a team known as the Vengers. They tried to replace Ben, but their true nature was eventually revealed to everyone.
In Cough It Up, Ben encountered Spanner again. Together, they defeated Psyphon, and the dehydrated Techadon Factory he was after was taken by Spanner. At the end of the episode, Ben revealed his suspicions regarding who he believes Spanner really is. 
In Blukic and Driba Go to Area 51, Ben learned how Blukic and Driba reached Earth. Ben also destroyed B.L.R.R.T. and arrested Benevelon.
In No Honor Among Bros, Rook was affected by Fistrick's "bro essence" and participated in the Golden Fist Tournament. Although he won the tournament, he arrested the participants afterwards, as it was an illegal tournament.
In Universe vs. Tennyson, Ben was dragged into a Celestialsapien court for recreating the universe in So Long, and Thanks for All the Smoothies. Ben was eventually found not guilty thanks to Chadzmuth.
Other episodes in Season 6 featured Ben's fight with the Rooters while Kevin's true past was revealed. The battle culminated with the Rooters' defeat and their Plumber status being revoked by the Magistrata.
Clyde 5 featured Ben's cousin Clyde Fife and how, upon obtaining the Cincotrix, he became a hero. 
Rook Tales and The Final Countdown featured Rook's former sensei, Kundo, who turned into a cyborg at the end of Rook Tales and got arrested at the end of The Final Countdown. 
The Ballad of Mr. Baumann featured Mr. Baumann and Sheelane, who was Baumann's fiancée. Eventually, Ben helped Baumann to successfully reunite with Sheelane and Vulkanus was defeated. 
Fight at the Museum featured Ben helping Kai to unsuccessfully protect the Orb of Pumapunku from Exo-Skull and Subdora who captured it for Maltruant. Ester also learned that Kai and Ben are meant to be together in the future from Spanner who was confirmed to be not Jimmy.
Breakpoint featured Ben infiltrating Fistrick's gang who were committing crimes by impersonating Ben. In the end, Fistrick and his gang were arrested.
The Color of Monkey featured Argit's new company and how Simian and Rojo caused trouble. They were eventually arrested. 
Vreedlemania features how the entire Vreedle family, upon reuniting, caused havoc in Bellwood until they were stopped by Ben.
Stuck on You featured Khyber enlisting the help of Skurd, a Slime-Biot, to operate the Nemetrix. Eventually, the Nemetrix was taken by the Plumbers, with Khyber being arrested. Skurd joined Ben as the Omnitrix because it has more DNA samples. 
In The Secret of Dos Santos, Ben helped Kai to find the Temple of the Sky. Exo-Skull intervened and Maltruant's history was revealed. Ben and Kai showed feelings for each other, with Kai even kissing Ben.
Malgax Attacks featured Vilgax and Albedo teaming up. Albedo used Malware's remains to create the Malware Armor for Vilgax to wear so that he could defeat Ben. Albedo then attacked Azmuth, which ended with Albedo's Ultimatrix being disabled. Meanwhile, Ben was being defeated by Vilgax and he apologized to Skurd for having him removed, and the two teamed up again to defeat Vilgax. Vilgax was eventually killed by his ship's core meltdown. Also, Malware's fate is unknown as the armor oozed out of Vilgax's petrified body.
In The Most Dangerous Game Show, Charles Zenith hosted a show which would decide who would marry Ben. Kai won the contest and all the girls who lost were rescued from the Null Void. Charles was arrested, Ben and Ester broke up on good terms and Ben and Kai beame a couple.
It's a Mad, Mad, Mad Ben World: Part 1, It's a Mad, Mad, Mad Ben World: Part 2, Fight at the Museum, Let's Do the Time War Again, The Secret of Dos Santos, The End of an Era, and A New Dawn featured the Time War. In the Time War, Maltruant put himself back together and orders Exo Skull and Subdora to find his missing parts. After becoming whole again, he orders Eon, Exo Skull and Subdora to get some Time Beast eggs for him. Even though Ben, Rook, Ben 10,000 and Paradox intervened Eon, who procured two Time Beast eggs for Maltruant.
After this, Maltruant went to the future and stole the Dwarf Star and the Annihilarrgh, and fused them to create his modified Annihilarrgh. Ben 10,000, Gwen, Kai and Spanner (revealed to be Ben's son, Ken) failed to stop him. Spanner brought past Ben and Rook to help. However, Eon arrived with a chariot pulled by a Time Beast. After Eon was betrayed, Maltruant escaped to the timestream with Ben and Rook following with the help of their Time Cycles. They eventually crashed to the past where Ben met George Washington and battled a young Vilgax.
Ben and Rook continued their chase which led them to a Contumelia ship. The Contumelia revealed that they create universes, they do not destroy them. Maltruant activated his modified Annihilarrgh to create the universe in his own image. However, the energy of the Annihilarrgh was absorbed by Feedback, who redirected it to Maltruant, dividing him into many parts. Paradox then came, revealing that Maltruant is trapped in a time loop in which he is doomed to lose. Ben and Rook then witnessed the creation of the universe after parting with Skurd, who joined his ancestors to seed life across the universe. At the end of this series, Ben called Gwen and decided that he, she, Rook and Kevin were to go on a road trip across the entire universe.