Allen is the product of a genetic experiment that would create a super Unopan capable of fighting the Viltrumites. Of all the attempts, Allen was the only fetus that survived the experiment with his mind and body intact. The process gave him super strength and speed, amazing healing abilities, high resistance to injury, the ability to travel in space unaided, near light-speed flight and reflexes, and telepathy. He was trained from infancy to fight and was never defeated until his first fight with an actual Viltrumite. When his people learned that the experiment was a failure, they scrapped it and Allen became a "Champion Evaluation Officer" and traveled space looking for beings strong enough to beat him so they could be used against the Viltrumites.
Major Story Arcs
Early in Invincible's career he was called by his dad to take care of an attacking alien. When Mark got into
space he started to fight Allen. During the fight Allen was saying strange things about having a champion and Mark being a replacement. Eventually Mark asked for a break and then an explanation. It turned out Allen was actually coming to Earth to evaluate it's champion instead of Urath. Thanks to Mark Allen was able to keep his job and he left for Urath.
When Allen returned to the Coalition of Planets he was shocked to hear there was a Viltrumite on Earth. He came back as quick as he could to warn Invincible. Invincible explained that his father was the Viltrumite and had already left Earth. Allen was shocked and confused because a Viltrumite has never done anything of the sort. He explained that the point of the Coalition was was to halt the expansion of the empire. He saw this as an opportunity to strike at the empire. He left Earth and returned to the Coalition.
After Allen left Invincible for a second time he returned to his home on Talescria, capital of the Coalition of Planets. Allen immediately told the good news to the council and they were as excited as he was. He left the council and went to his girlfriend's apartment. Telia, his girlfriend, is another species and a very sexual one at that which proves troublesome for Allen whose people have forbid any form of physical love. Allen eventually breaks down and allows himself this moment with Telia. Afterwards Allen and Telia went out to eat where Allen enjoyed some of his favorite food. During the meal a Viltrumite scouting party attacked Allen. The group demanded to know everything about what he told the council but Allen denied them anything they didn't know and the party quickly eviscerated him. Luckily Allen was saved and put into a statis pod that allowed him to heal.
After months of healing Allen awoke and accidentally ripped apart of the machine with his newfound strength. Shortly after a nursebot gave him a physical Thadeus, head of the council, entered and revealed that Allen's body and changed and adapted to his recent beat down making him near or at Viltrumite power levels. Allen questions this because no clearcut power level has ever been found for a Vitrumite. Thadeus asks for the nursebot to leave and reveals he is in fact a Viltrumite rebel. He goes on to say that Invincible may be the key to ending the reign of their empire. However, he explains that Allen must only report to him now because he believes there may be a mole in the council.
Back to Earth
During his talk with Thaedus, Allen is given the task of returning to Earth, and asking Invincible to speak with Thaedus about joining their cause. While heading towards Earth, not knowing who it is, Allen is attacked by The Immortal. Invincible catches word of Allen and Immortal fighting, and flies into space to stop it. After the fight being broken up, Allen and Immortal reconciled, and Allen told Invincible that he needed to speak to him.
During the chat, Allen told Invincible of his being attacked, his power boost, and his working with Thaedus. Allen asked Invincible if he'd come with him to Talescria, and Invincible told him that he doesn't want to, and that he's got too much he has to deal with. But later, Invincible informs Allen of his little brother, his father being taken for execution by the Viltrumites, and his discovery that his dad's scif-fi novels hold the key to defeating the Viltrumites. And with his new information Allen says goodbye, and heads back to Talescria.
While flying back, Allen notices a Viltrumite ship. And they noticed him. Out came a female Viltrumite, ready to fight. While fighting, she and Allen are exchanging remarks, and Allen discovered that the ship he came into contact with was none other than a Viltrumite prison ship. During the battle, Allen remembered his talk with Invincible about how his dad was taken in for execution. So, Allen formed a plan to throw the fight, and free Omni-Man while on the inside.
The Start of a Friendship
In prison Allen crosses paths with Omni-Man and sends him a telepathic message telling him that they'll talk later. Later, Allen discovered that his telepathic abilities would allow him to speak with Omni-Man while they were inside their cells. Allen tells Nolan of his orders from Thaedus. He speaks of the importance of Invincible in the coming war between the Coalition of Planets and the Viltrum empire. Allen informs him of his newfound strength and his plan to free Nolan from prison. At first, Nolan is reluctant to betray his people. Allen continues to tell Nolan all he knows about the sci-fi novels, Invincible's new younger half-brother, and eventually he begins to tell him of other things. Eventually this led to Nolan talking about other things as well. Many things were discussed while Nolan awaited execution. Eventually they even talked about their many encounters in Earth's orbit, years ago, when they knew nothing about each other. Through their talking, a bond started to form, and they became friends. Allen was no longer there to rescue an ally, he needed to rescue his friend. So they discussed plans of escape, and were interrupted many a time, with failed execution attempts.
Eventually, Allen found the right time to escape when the Viltrumites attempted to execute Nolan. Allen followed his three step plan. Step One: Cause damage, and trip alarms to create a distraction. Step Two: Free the prisoners so they can cause even more of a distraction. And Step Three: Scan the prisoners as they escape, to see if any of them are formidable enough to aid him and Nolan in their escape efforts. Allying himself with the prisoner Battle Beast, Allen heads to the execution room to save his friend! Allen saves him just in time, but they get overrun by prison guards. With quick thinking, Allen punches a hole in the side of the ship, thus suffocating all of the guards.
The only people to survive were Allen, Nolan, Battle Beast, and two Viltrumites. Battle Beast handled one of them fairly quickly, and Allen and Nolan used teamwork to finish off the last one. Nolan tells Allen that they have plenty of time to gather their supplies, because he informs Allen that there aren't very many Viltrumites left. He tells Allen that there are less than fifty pure-blooded Viltrumites left in the whole universe. Nolan told Allen that previously, the enemies of the Viltrumite empire created a virus unique to their genetic code that wiped out 99.9% of the Viltrumite population. Nolan told Allen that the only reason they wanted Earth, was to use it as a breeding camp, because a human's DNA is almost 100% compatible with a Viltrumite's. With this news, they head back to Talescria.
Preparations for War
While on Talescria, Allen lets Nolan stay at his apartment. Allen and Nolan meet with Thaedus and are given their first mission of finding the Space Racer's gun, which is a gun that can shoot through anything, but it can only be fired by the Space Racer. Upon finding the gun in an asteroid belt where Nolan left it, they discovered that the Space Racer was still alive, even after Nolan burying him alive almost one hundred years ago. With a little explaining of Nolan's reformation by Allen, and some apologizing on Nolan's behalf, the Space Racer agreed to come with them to Talescria, and join their side. Once back on Talescria, they were given a series of missions that include: Gathering vicious Rognarr creatures, collecting Klaxus plant poison, finding Tech Jacket, finding space sharks, and finding Battle Beast.
Time for War
The time for war has arrived, and Allen and Nolan have returned to Earth! They've convinced Invincible to join up, and along for the ride came Tech Jacket and Invincible's younger brother Oliver. En route to Talescria to lead the attack on Viltrum, a group of Viltrumites decimated their ship! A fight erupted, and soon after, the Grayson family could not be found. Allen and Tech Jacket hid from sight, and soon became good friends. After a few days, they were found and saved by a squad led by the Space Racer. Returning to Thaedus, Allen and Tech Jacket were given the orders to continue their initial attack on the Viltrumites.
Invasion of Talescria
About to officially start the war, Thaedus gives a speech to the Coalition of Planets. Mid-speech the Viltrumites come crashing through structures all over Talescria. Everybody, including Allen, joins in on the fight, and the Grayson family has arrived just in time! The mole has finally been revealed, and it turns out he's the one who led the Viltrumites to Talescria.
Finishing the Fight
After tons of bloodshed the Viltrumites have retreated, and this time, they're not escaping. Allen and company follow the Viltrumites to Viltrum, before they have time to plan for another attack. They have an intense fight in orbit of Viltrum with Grand Regent Thragg and his squad. Allen and Tech Jacket cover for Nolan, Invincible, and Thaedus while they crash into Viltrum. Their cover was a success, Viltrum was obliterated. But this move only angered Thragg, who turns out to be almost more powerful than their entire group combined. With Thaedus killed, and everyone severely injured, they had to retreat.
With Thaedus dead, and the last remaining Viltrumites in hiding, Allen was promoted to leader of the Coalition of Planets. And now, everyone is supposed to call him "Great Allen," but he just jokes about it, and remains the same. Invincible wakes up in a panic, and informs Allen that he needs to check Earth for Viltrumites. Allen lets him go to check it out, but informs him that he's doubtful, and the Viltrumites don't pose much of a threat. He also tells him that he's gone through many precautionary measures to protect the Coalition of Planets and other planets that were formerly owned by Viltrumites.
While hanging out, Allen was given an info tablet that contained Thaedus' final words for him. The tablet revealed the hidden location of a perfected Scourge Virus, and Thaedus stated that unleashing it this time will kill every single Viltrumite. He is told to ignore his attachment to his Viltrumite allies, and unleash it, for the good of the universe. Thaedus' last words on the tablet read "Whatever you do, make certain that I did not die in vain." So now, Allen must face a tough decision: Let the Viltrumites live, thus keeping his friends alive. Or unleash the Scourge Virus, killing his friends and all Viltrumites for the good of the universe.
With Nolan still on Earth, Allen and Telia watch over Oliver while also making sure his recovery is going well. While returning to Talescria, Nolan reveals through a transmission that the Viltrumites are indeed on Earth. Allen holds a meeting with Nolan to discuss what should be done about the Viltrumites. Nolan believes that after years of living on Earth, the Viltrumites could change, while Allen doesn't share the same optimistic point of view. Allen asks Nolan to leave and ponders the decision he should make.
While late-night thinking, Allen asks Telia if doing something horrible for the sake of the universe makes him a bad person.She replies that making hard decisions is a part of his job. Allen brings Nolan in to talk, and reveals that he has made the decision that he will personally introduce the Scourge Virus to Earth's atmosphere. Allen had to tell Nolan because he valued his friendship far too much, and he tells him that he's sorry. Nolan informs Allen that releasing the virus will possibly eradicate the human race as well, and Allen states that he knows this. The two proceed to fight, while both tell each other their differing views. Oliver sees Allen beating up Nolan, and starts to fight Allen. The fight is broken up by Allen's soldiers. When Oliver hears what Allen is going to do, he decides to join him. Allen asks for Oliver's help in convincing Invincible and leaves, leaving his former friend and ally, Nolan, bloody and beaten.
Powers & Abilities
In addition to his super strength (able to lift/press at least 1,000,000,000 tons) and speed (FTL flight), amazing healing abilities, high resistance to injury, the ability to travel in space unaided, light-speed reflexes (dodging an FTL Viltrumite ship), telepathy and fighting abilities, Allen has discovered that he has another power. After being beaten past the limits of his body by three, fully trained Viltrumite warriors, Allen didn't die. Instead he healed and came back stronger than ever. He says that for some reason, whatever doesn't kill him, makes him stronger, and since he already survived something that should have killed him, maybe nothing can. He also speculates that since he may be "unkillable", he might be immortal. After coming back from his beat down by the Viltrumite trio, Allen is noticeably bigger and more muscular, but otherwise looks the same.
A Favorite of Fans
Despite Allen's few appearances he is widely considered a favorite character by Invincible fans. Even Robert Kirkman himself has stated Allen is his favorite and will never die. He has even joked about giving Allen his own ongoing title.