As a tadpole he achieved a perfect score on his GATs before he became the first thinker.
In his youth, Azmuth enjoyed a relationship with a female Galvan named Zennith, and while on a date with her witnessed a planetary alignment. The sight inspired Azmuth to create a powerful sword, which sadly brought his romance with Zennith to an end as she disapproved of his creation. Later realizing for himself the dangers of the sword, Azmuth began to dedicate himself to peaceful science, eventually creating the Omnitrix, hoping to create a means for the races of the galaxy to live in harmony. He used the Omnitrix's Scan Mode to gather the DNA of thousands of species over hundreds of years. He also hoped that it might redeem him in Zennith's eyes.
In Secret of the Omnitrix, Azmuth was found in his lab on Xenon by Cannonbolt, Tetrax, and Myaxx, where he is eventually convinced to turn off the Omnitrix's self-destruct. He also unlocked Way Big so Ben could defeat Vilgax. Azmuth modified one of Vilgax's drone's heads to be able to leave Xenon in it, taking Myaxx with him.
Destroy All Aliens revealed that Azmuth, inspired by Ben's obvious concern for his family, decided to reunite with his own after a long absence. After detecting a strange signal coming from the Omnitrix (caused by Gwen casting a dismantling spell on Upgrade), he contacted Tetrax and arranged to meet the Petrosapien on Earth. Traveling to Earth using his drone-head ship, Azmuth disguised it as a semi-truck and headed for his rendezvous with Tetrax. He was then contacted by his concerned father, who watched as a strange light-coming from the malfunctioning Omnitrix-shone over Azmuth and his ship crashed.
When a malevolent looking To'kustar appeared on the video feed following Azmuth's disappearance, his father came to believe that Azmuth had perished at the hands of the giant alien. Donning a set of Mechamorph Armor created by Azmuth, his father traveled to Earth, where he ran into Ben. At first unaware that Ben was transforming between different alien forms-unable to revert to human due to Tetrax activating a feature of the Omnitrix-he demanded to know the whereabouts of the To'kustar. Ben had fought the giant alien only for it to disappear; he and Azmuth's father would later discover that the being had been downloaded into the Omnitrix.
Following the To'kustar's escape from the Omnitrix, the Tennyson family realized that the giant being was Azmuth himself, mutated by the malfunctioning device and so disturbed by the change that he was unable to recognize his own father or friends. Eventually they brought him out of it, and Azmuth used the Mechamorph armor to repair the Omnitrix and revert himself back into his normal Galvan form. Azmuth's father then revealed his own Galvan form, which was younger than that of his son-this was due to Azmuth transferring his father's mind into a clone body.
Father and son forgave each other for their misdeeds, with Azmuth confessing that he should have warned his father about the armor's tendency to increase aggression. Azmuth also helped restore Ben's parents, who had likewise been transformed into aliens, to normal. He commented on the Omnitrix's malfunction being caused by a mana overload, confusing Gwen, who was ignorant at the time about her Anodite lineage. Azmuth and his father then returned home.
Five years prior to Omniverse
In a flashback in Trouble Helix, Azmuth was working on a second Helix with Albedo, where Max comes in, asking him to fix the malfunctioning Omnitrix, to which he refuses. XLR8 comes and makes him by breaking one of his machines. Azmuth later revealed his hand in the creation of the Galvanic Mechamorphs through his experiment called the Helix, in the intent of making Galvan B habitable. He also revealed he had been working for many years on trying to heal Malware, a Galvanic Mechamorph whose life code is corrupted and incomplete.
During a flashback in Showdown: Part 2, Azmuth helps comfort and advises Ben, after Ben lost Feedback.
Azmuth returned in Good Copy, Bad Copy. Azmuth revealed that Albedo used to be one of his assistants, and that he had came to take the Omnitrix copy from Albedo. Azmuth states that only one Omnitrix is allowed in the universe (though later on, Azmuth began to create an improved version).
In War of the Worlds, Azmuth and Paradox warn Ben that the Highbreed are conquering and destroying planets, and their fleet was heading towards Earth. Galvan Prime has already been destroyed and its destruction would be the beginning of the end. Although he doesn't want Ben to fight, Azmuth realizes that there's no stopping him and activates the Master Control for the sake of the battle. When the Omnitrix was reset by the DNA wave Ben used to stop the Highbreed (locking the Master Control), Azmuth left to help rebuild Galvan Prime without reactivating it, telling Ben to "have fun figuring it out."
In The Vengeance of Vilgax, when Ben and Kevin tried to hack the Omnitrix, Azmuth contacts Ben telling him not to tamper with it, stating that he will learn how to activate the Master Control when the time is right. When an accident unleashes Chromastone, Goop, Spidermonkey, and Way Big from the Omnitrix, Azmuth instructs Ben to reabsorb the alien forms into the Omnitrix. Dissatisfied with what happened, Azmuth also tells Ben that he won't help him again.
In Primus, Azmuth wields the Omnitrix in order to protect Primus from Vilgax, but is defeated and Vilgax takes the Omnitrix from him. Azmuth himself attributes his defeat to his "skills being a little rusty." He is saved by Ben, who manages to trick Vilgax by showing him how to use the Omnitrix. Ben gets Vilgax to transform into Goop, allowing Ben to get the upper hand and remove the Omnitrix from Vilgax. In the end, even though Azmuth hasn't forgiven Ben for damaging the Omnitrix, he allows him to keep it anyway.
In The Final Battle, Myaxx informs Azmuth that the Ultimatrix was stolen. Myaxx also shows security footage of Ben, or someone who looks exactly like him, stealing the Ultimatrix; Albedo, to which Azmuth replied "No! Not him! Anyone but him.". In the later half of the episode, Azmuth answers Ben's plead for help. He explains to Ben that the Omnitrix was originally meant for Max. When Ben says he let Azmuth down, he agrees. Azmuth tells Ben that "winning isn't so easy without the Omnitrix", making Ben realize that the only way to defeat Vilgax would be to destroy the Omnitrix. Azmuth reveals he thinks that Earth has lovely weather.
Azmuth returns to Ultimate Alien in Map of Infinity, right after Ultimate Aggregor defeated Ben and his team. He tells Ben and his group about the Map of Infinity, an item Ultimate Aggregor is planning to steal in order to go to a location called the Forge of Creation. He also mocks the Ultimatrix, saying it is "pathetic workmanship." Azmuth reveals that he is constructing a third Omnitrix. He also refuses to let Ben have it, because he is too reckless and requires much patience. In addition, it wasn't completed anyway. He also thinks that adding an evolutionary feature to the Ultimatrix was a terrible idea, that is just "begging for trouble". He introduces Ben and the team to Galvan Mark II, Galvan Prime rebuilt. He later puts Max in a tube to replace his damaged nervous system, caused by Ultimate Aggregor.
In Perplexahedron, Azmuth was not happy with Ben's failures over losing three pieces of the Map of Infinity; he told Ben where the final piece was.
In The Forge of Creation, Azmuth was still not happy with Ben's failure and his loss of all four pieces of the map; he scolds Ben and his team about letting Ultimate Aggregor beat them each time when they had four opportunities to stop him. After Paradox transforms Alien X back to Ben, Azmuth has an argument with Paradox about Ben and his friend's ability to save the universe this time. Azmuth also says that trusting Ben with the Omnitrix was a "grave mistake" though Paradox had said that it was not a mistake at all, and that he and Azmuth knew the reasons why all too well. Azmuth resentfully begins to reveal that Paradox had told him that Ben was a legendary being born with incomprehensible, immeasurable power, and that he would someday do something amazing, as it was his "grand destiny," but Paradox interrupted him, saying that there must be "no spoilers."
In The Transmogrification of Eunice, Azmuth is little in Sunder and Ben's battle for the Unitrix and seeing Ben and Sunder fighting in a muddy area. He is also the one who hired Sunder to retrieve the Unitrix. He had told Ben and his team about the Omnitrix prototype called the Unitrix. He had an argument with Ben about Eunice's life but, after being impressed by Ben's strong defense over Eunice and his belief about his aliens, he agreed to a compromise and allowed her to live a free life as one of his assistants. He stated that he always needed help tending to Primus.
In Simian Says, Eunice contacted Azmuth about the degradation of the Arachnichimp DNA sample on Primus; he angrily told her to send Voliticus Biopsis to get a fresh sample.
In The Ultimate Sacrifice, Azmuth saves Ben from death and frees the Ultimates from the Ultimatrix. Ben has regained Azmuth's trust, it seems, as he was willing to sacrifice himself for his aliens' freedom.
In Solitary Alignment, Azmuth becomes involved with the Forever Knights by claiming that the sword Sir George used to fight Dagon with is his, which leads Ben to question him about the first knight. Azmuth reluctantly agrees to tell his origins and one of his early inventions.
In The Ultimate Enemy: Part 2, Azmuth came to reclaim Ascalon and the Ultimatrix, and in return gave Ben the new Omnitrix after Ben proved himself worthy of having the Omnitrix. Azmuth didn't add the Ultimate Forms to the new Omnitrix, and nothing will replace them in Ben 10: Omniverse.
In Showdown: Part 1, Azmuth was ambushed by Dr. Psychobos, Khyber, and his dog. They turn Khyber's dog into Omnivoracious to kill Azmuth. When she's busy battling Ben, Azmuth makes a whistle out of a bone and turns Omnivoracious into Vicetopus to hold Dr. Psychobos captive.
In Showdown: Part 2, Azmuth helped plan together on how to stop Malware from taking over Galvan Mark II. He, along with Gwen and Rook, traveled to the remains of Galvan B to find a solution while Ben and Kevin are keeping Malware busy. Azmuth eventually finds the Helix, which he believes could be beneficial. Azmuth is seen again, bringing Feedback the Helix so he can use its powers to defeat Malware. Azmuth also revealed that he brought the Galvanic Mechamorphs back to life and he watches as Feedback finally defeats Malware for good. Azmuth appears again in 16 year old Ben's subconscious, telling 11 year old Ben that Ben never learns anything just from winning and says that Ben could learn something from losing Feedback.
Azmuth makes an appearance at the end of A Fistful of Brains, as he was kidnapped by Albedo and Khyber, and was trapped within a machine. In next episode, For a Few Brains More, Albedo drained Azmuth's intelligence, causing Azmuth's "pre-brain" to take control; As a result, Azmuth became a childish buffoon. After Azmuth was turned back to normal, he modified the Ultimatrix to turn Albedo into an eleven-year old clone of Ben as punishment. He also said that Ben needs to stop hitting the Omnitrix so hard, because whenever he transforms into an alien, the impact of his hit sets the timer to random.
Azmuth is mentioned in the case during Universe vs. Tennyson, in which Chadzmuth indicates that the changes in his appearance and voice over the years have been the result of Celestialsapiens redesigning the universe.
In Malgax Attacks, Ben comes to Azmuth, asking him to separate Skurd from the Omnitrix. Azmuth is fascinated by Skurd, having believed that the Slimebiote race was extinct. Though he tries to dissuade Ben from his decision, Azmuth agrees to use ionic particle surgery to remove Skurd. He then places Skurd in a container, hoping to study him. When Vilgax and Albedo attack Galvan Prime, Azmuth chooses to deal with Albedo. When he confronts his former assistant in his lab, Albedo (as Ultimate Rath) seemingly vaporizes him. However, Blukic and Driba discover that Azmuth had actually teleported himself at that exact moment, and manage to reconstitute him. Azmuth uses a device to shut down Albedo's Ultimatrix, once again trapping him in the form of an eleven-year old Ben. He then reveals to Albedo that he became the first thinker for coming up with possible contingency plans, such as a failsafe for preventing the misuse of an Omnitrix. After Vilgax is defeated, Azmuth commends Blukic and Driba for being smart enough to recognize the clue he left behind, adding that the reconstitution process has fixed his sciatica, leaving him feeling "like brand new."