Aggregor

Aggregor is an Osmosian warlord. His main objective is to get to the Forge of Creation and absorb the powers of a baby Celestialsapien (which he refers to as the "Ultimate Prize") so he can become omnipotent. To achieve this goal, he absorbed the abilities and forms of five powerful aliens he captured from the Andromeda Galaxy in order to become strong enough to search for and reassemble the four fragments of the Map of Infinity, the one item which will lead him there.

Appearance
Aggregor's appearance is similar to that of a human. However, he has small flesh-colored horns coming out of his head and red eyes ringed with Black marks (a sign that an Osmosian has recently absorbed energy). He has long black hair. He wears a brown knee-length, open-chested tunic, baggy jeans, black calf high boots, and wields a spear-like weapon that he can use to fire blasts of red energy (presumably plasma or electricity).

After the absorption of the Andromeda aliens, Aggregor went through a mutation similar to Kevin's, becoming a powerful, chimeric amalgam of the five aliens. Unlike Kevin's mutations, Aggregor's mutation was more refined and balanced in appearance, rather than a random mixture of parts, and not lacking the full potency of the five aliens powers (the result of a special machine he used to bypass the normal limitations of his absorption powers). In this form, he has Bivalvan's legs and hands, Galapagus's torso armor(darker color), Andreas' frame, and arms, P'andor's faceplate on his neck and seal on his chest (Galapagus's darkened coloring), and a Ra'ad-based head and hair. His eyes are blood red and he is also much taller than before, standing at approximately 10 feet tall.

Powers and Abilities
Being an Osmosian, Aggregor has the ability to absorb matter and energy from anything in order to use it in various way. While Kevin relies more on matter absorbing powers, Aggregor has mastered his powers, and prefers absorbing the energy of other life forms, acquiring 1/10 of the creature's powers without mechanical aid (this is the biological limit for Osmosians). Unlike Kevin, (at least until he used a machine) the powers and abilities he absorbs don't drastically change his appearance (due to his advanced age as Kevin 11,000 was able to do the same: for example, when Aggregor absorbed powers from a Geochelone Aerio, his appearance stayed the same, though he could now open six holes on his torso at will to use Geochelone Aerio powers. Also, while Kevin, when he absorbed powers from the Omnitrix aliens, left them unharmed (as he absorbed the transformative energy of the Omnitrix rather than the energy of the aliens' themselves), Aggregor absorbs all of his victim's energy, leaving behind nothing but a desiccated skeleton/shell (except when he used a special machine to surpass his absorption limitations which allowed him to absorb the aliens' bodies along with their powers by turning them into pure energy).

In addition to his absorbing powers, Aggregor is a highly skilled hand-to-hand combatant and has a spear-like weapon that he can use to fire blasts of red energy that can disrupt other energy fields, stun his opponents, or hurt them. As seen in Andreas' Fault, he can use his spear-like weapon to summon his ship as well as lift objects with an electromagnetic aura that is the same/similer energy from his spear. In Fused, Aggregor explains that his weapon is designed to combat electromaniputive species, as seen when he used it to redirect Brainstorm's electrical attacks.

Much like Vilgax, Aggregor uses robot drones as his army rather than living soldiers, though his robots are more humanoid in shape and stature than Vilgax's. However, he prefers to carry out his plans himself rather than let his minions do the work for him, unlike Vilgax and the Highbreed. He captured and re-captured the five Andromeda aliens by himself, and didn't mind to disguise himself as a Plumber to do it.

After his mutation in Ultimate Aggregor, Aggregor absorbed the five aliens he kidnapped from the Andromeda Galaxy, resulting in him having their combined powers. His new abilities included
 * Andreas's super strength and shockwaves.
 * Bivalvan's durability and hydrokinesis.
 * Galapagus's immunity to mana-based attacks and aerokinesis.
 * P'andor's radioactive energy beams, heat generation and heat/cold immunity.
 * Ra'ad's electric blasts, flight and mind reading.
 * Ultimate Aggregor's powers allowed him to travel through space unassisted, meaning he didn't require his ship anymore.

Weaknesses
Before he absorbed the Andromeda Aliens, Aggregor was very dependent on his spear as shown in the first five episodes he appeared in (particularly Escape From Aggregor and Fused). He was shown to be hurt by Gwen's mana attack as shown in Ultimate Aggregor. Ultimate Aggregor was harmed by Max's plasma pistol and Ultimate Cannonbolt's attacks. It should also be noted that the only reason Ultimate Cannonbolt lost was because he was caught off guard. As seen in The Forge of Creation, during his fight with Ultimate Kevin, Ultimate Aggregor was harmed by Jetray's neuroshock blasts, Swampfire's fire blasts and Brainstorm's electric blasts. Without his spear, Aggregor is vulnerable to energy-based attacks unless he were to use his natural absorption powers to absorb them. However, because he lacks experience with absorbing pure energy, doing so could be potentially dangerous to his physical and mental state (though he would likely be unaffected later, as he is already apathetic and unstable to begin with). According to Dwayne, Ben could've defeated Aggregor in Fused had he not used an electrokinetic alien.

Ben 10: Ultimate Alien
In Fame, after Bivalvan was defeated, he explains that Aggregor captured him along with four others but they managed to escape to Earth. At the end of the episode, instead of the Plumbers who Bivalvan was expecting to send him back to his home planet, Aggregor appeared. His first line was "No one escapes me, Bivalvan" and he captured him.

In Escape From Aggregor, Galapagus told the tale of how he and the other four aliens were captured and escaped. Aggregor revealed that his plan was to absorb all the powers and abilities of the five aliens he captured using a machine he had built back on Osmos V in order to become strong enough to gather and reassemble the four pieces of the Map of Infinity so he can travel to the Forge of Creation and absorb the powers and abilities of a newborn Celestialsapien so that he can become omnipotent (which he refers to as the "Ultimate Prize"). At the end of the episode when Ben and the others sent Galapagus back to Aldabra, the Plumber that was transporting him is revealed to be Aggregor in disguise.

In Too Hot To Handle, after Ben, Gwen and Kevin succeeded in subduing P'andor and had him taken off the planet. Aggregor attacked the ship transporting him before abducting it. Aggregor's attack had caused the glass to be smashed open, resulting in the pilots being flung into space while he recaptured P'andor.

In Andreas’ Fault, Aggregor found Andreas buried underneath the remains of a Forever Knights' castle before transporting him back to his ship and putting him in a stasis pod alongside Bivalvan, Galapagus, and P'andor with only Ra'ad remaining to be recaptured, after which he states that then "the fun begins".

In Fused, Ben, Gwen and Kevin finally met Aggregor face to face. It was revealed by Ra'ad that Aggregor was using the signal of the Ultimatrix to locate the aliens. Ra'ad attempted to destroy the Ultimatrix to prevent Aggregor from finding him, but the Ultimatrix had attempted to scan his DNA at the same time, resulting in Ra'ad being trapped in the Ultimatrix and his form being the only one Ben could turn into. When Aggregor arrived and defeated Kevin, Ben transformed into AmpFibian. Aggregor attempted to use AmpFibian as a replacement for Ra'ad, but Gwen used a teleportation spell to teleport the trio to Kevin's warehouse. Aggregor returned to his ship to have his sensors track the Ultimatrix signal, but it was offline because of Ra'ad's disabling of it. Gwen and Kevin rebooted the Ultimatrix to separate Ben and Ra'ad, allowing Aggregor to find them again. Knowing he would be coming, Ra'ad quickly fled just as Aggregor came in through the roof again. After dispatching Kevin and Gwen, Ben faced off against him as Brainstorm. Unfortunately, Aggregor used his spear to ground Brainstorm's lightning attacks and neutralized his electrokinetic powers with the red energy blast from his weapon (nearly killing him in the process). He then attempted to change Brainstorm into AmpFibian for his plan by stabbing and twisting the Ultimatrix's faceplate with the blade of his spear. However, Ra'ad (having been given a lecture by Kevin) returned to save Ben. In the clash between Ra'ad's lightning attacks and the red energy blast of Aggregor's spear, the warehouse exploded, but Ben and Gwen were able to escape while Aggregor transported Ra'ad back to his ship during the blast. With all five of his prisoners recaptured, Kevin feels that Aggregor has won, but Ben, having scanned all five aliens, vows to use their powers and abilities to stop Aggregor.

In Ultimate Aggregor, it was shown that after Aggregor escaped the warehouse's explosion with Ra'ad, he traveled out into the desert to call his ship and transport him. However, he found himself ambushed by Plumber agents out to get him for his murder of their noble comrades and his kidnapping of aliens. Unfortunately, Aggregor was prepared and unleashed a torrent of laser cannons to bring down the entire platoon while he transported himself and Ra'ad up to his ship. Just as he was about to make a jump to his home planet, Osmos V, the lead Plumber of the ambush used one of the downed ships to take out the hyperdrive of Aggregor's ship. Unable to leave the planet, Aggregor had to come up with a new plan. When Ben and his team tracked his ship, they were attacked by Aggregor's robots. When Ben as Lodestar boarded the ship, it self destructed. Fortunately, Ben was able to survive thanks Lodestar's magnetic abilities pulling him back together. Meanwhile, Aggregor broke into Los Solodad with intent on using the Entropy Pump from Paradox's old time-traveling experiment as a replacement for the machine on his home planet. Upon discovering where he was, Ben and his group stormed Los Soledad, charging through the remainder of Aggregor's robots. Needing more time, Aggregor used a mind control device to have the five Andromeda aliens attack Ben and the others. After being freed from the control, Aggregor instantly recalled the five aliens. When Ben's team confronted Aggregor, Kevin warned Aggregor not to go through with his plan, mentioning that absorbing raw energy causes Osmosians to go insane, which explains Kevin's acts in the original series. Aggregor however, refuses to believe it, claiming that the powerful Osmosians told that to the weaker Osmosians to control them. Before Kevin could convince him otherwise, Aggregor blasted him then used the Entropy Pump to transfer the powers and abilities of the five aliens into himself. Ben as Humungousaur managed to stop the pump before it destroyed reality. Unfortunately, it was too late as Aggregor had completely absorbed the five aliens, transforming himself into his mutated state, a massive chimeric mutant, named Ultimate Aggregor.

Continuing in Map of Infinity, Ben, enraged that he was unable to save the Andromeda aliens, viciously attacked Ultimate Aggregor, demonstrating incredible Humungousaur's strength more then ever before. Unfortunately, Humungousaur's attacks did nothing to Ultimate Aggregor he was invulnerable as Bivalvan's armor. Thanks to Galapagus, Ultimate Aggregor was also immune to Gwen's mana attacks. Showing off his newly acquired strength, powers, and abilities, Ultimate Aggregor toyed with Ben's team and easily defeated them all, greatly damaging Grandpa Max's nervous system in the process. After knocking Humungousaur out with a powerful seismic strike that demolished most of Los Solodad in the process, Ultimate Aggregor left, now able to travel through space on his own. Azmuth then reveals that the reason Aggregor absorbed the aliens was so that he had the power to find the four fragments of the Map of Infinity, which will allow him to enter the Forge of Creation and obtain the most powerful force in the universe. In order to stop him, Ben and the others must keep him from getting at least one of the fragments. After going through a temple filled with booby traps on Mykdl'dy, a fire/ice planet, Ben and the others nearly reach the first piece, but due to Ben and Kevin being forced to hold up the door that leads to the chamber holding the piece and Gwen being hit by a poison dart, they were powerless to prevent Ultimate Aggregor (who used the trio to discover the traps and lead him to the first fragment) from escaping with the first fragment of the map. Despite this loss, Ben vows more than ever to make Ultimate Aggregor pay for his crimes.

In Deep, Ultimate Aggregor invaded the core of Piscciss to steal the second piece of the map, which was in the form of the planet's anti-gravity generator. With the ocean planet falling apart, Ben had no choice but to save the planet and let Ultimate Aggregor escape.

In Where the Magic Happens, the trio chased Ultimate Aggregor to the Door To Anywhere, which Ultimate Aggregor used to enter Yahwahtacsip. Gaining the assistance of Charmcaster, the trio entered the realm of mana to follow him. When the group was in a battle with Adwaita, Ultimate Aggregor used it as a diversion to attack Adwaita from behind and steal the Alpha Rune from him, the third piece of the map, before thanking Ben for helping him again and disappearing out of the realm. With only one more piece left, Ben becomes more determined than ever to stop Ultimate Aggregor.

In Perplexhahedron, Ultimate Aggregor enters planet Perplexhahedron, which was built by Paradox to protect the fourth piece of the Map of Infinity. He uses the map's other pieces to enter the planetoid and makes his way through the maze, where he encounters Gwen and leaves her to freeze in an snow room. He finally makes it to the fourth piece but has a battle with Ben, who turns into Ultimate Cannonbolt. Despite his best efforts, Ben is beaten and loses the final piece to Aggregor, who escapes the crumbling planetoid, now possessing the key to entering the Forge of Creation. Despite losing the battle for the map, Ben and the others vow to win the war by stopping Ultimate Aggregor once and for all.

In The Forge of Creation, Ultimate Aggregor attacks both Bens, Kevin, and Gwen in the Forge of Creation and easily defeats two of them, leaving the Bens to fight him. 16 year old Ben turns into Ultimate Swampfire and grows vines to hold him in place while 10 year old Ben transforms into Stinkfly and shoots goo at him. Aggregor breaks free and knocks down Stinkfly, who transforms back into young Ben. He shocks Ultimate Swampfire, who turns back to Ben as well. Young Ben offers his Omnitrix to Kevin who can absorb the energy and fight Ultimate Aggregor, but Kevin instead absorbs the energy from the Ultimatrix, creating a blue energy sphere surrounding the area. Ultimate Aggregor enters and prepares to absorb the newborn Celestialsapien, but is stopped by Ultimate Kevin, who has transformed into a horrific massive mutant, towering above Ultimate Aggregor. Ultimate Kevin assaults Ultimate Aggregor with his powers and absorbs his energy, transforming him back to normal and leaving him unconscious. Though Ultimate Kevin, gone insane for absorbing the Ultimatrix energy was about to kill him, he is persuaded to spare his life by Gwen and the Bens. Dwayne McDuffie confirmed that after he was defeated by Ultimate Kevin, Aggregor was taken into custody by the Plumbers.

Appearances

 * Fame (first appearance)
 * Escape From Aggregor
 * Too Hot To Handle
 * Andreas’ Fault
 * Fused
 * Ultimate Aggregor
 * Map of Infinity
 * Deep
 * Where the Magic Happens
 * Perplexahedron
 * The Forge of Creation

Trivia

 * According to Dwayne, Aggregor is a much, much greater threat than Vilgax, even before he absorbed the powers of the Andromeda aliens.
 * According to Dwayne, Kevin has more experience with absorbing pure energy than Aggregor.
 * According to Dwayne, Ultimate Aggregor didn't just "stand there in shock" when Ultimate Kevin attacked him; rather he tried to absorb his attacks but could not due to his inexpriance in absorbing that kind of energy.
 * According to Dwayne, Aggregor isn't a high ranking official, great warrior or dictator of Osmos V, despite him owning a spaceship and robot minions. Dwayne McDuffie just said "wait and see" of how he gets his hands on those, possibly meaning Aggregor will return.
 * Aggregor is one of the few villans that was never beaten by Ben himself.
 * In Fused, Ben says that he has the DNA of all the Andromeda Aliens and will use them against Aggregor, but he never used any Andromeda aliens against Aggregor himself (however, he did use Terraspin to fight Aggregor's soldiers).
 * Aggregor's name has been used in 2 episodes: Escape from Aggregor and Ultimate Aggregor.
 * Aggregor has none of the previous villains weaknesses (except being mad with power). Instead of sending his henchmen like the Highbreed, he prefers to carry out the tasks himself. He always thinks his plans through, unlike Darkstar. Like Vilgax, he is arrogant, but not enough to underestimate his enemies and has the power to back up most of his threats.
 * Aggregor has appeared in one season more times than any other villain, or recurring character, with a total of eleven appearances in Ultimate Alien: Season 1.
 * Aggregor's appearance is very similar to a Zabrak (more specifically Eeth Koth, Agen Kolar, Savage Oppress, and Darth Maul) from Star Wars. It is confirmed that Aggregor's appearance is not based on a Zabrak.
 * Aggregor refers to Kevin, a fellow Osmosian, as a "hatchling", a reference to their difference in age, power, and experience.
 * Aggregor has been shown to be a dangerous enemy, not even the Plumbers' are able to stop him. He has been shown to be capable of defeating Plumbers of even Magister rank (the highest known rank)(he even murdered Magister Prior Gilhil). He also seems to show little fear of the Plumbers (though at one point he tried to avoid conflict with them) or possible retribution by the Plumbers entire organization for his crimes.
 * It is interesting to note that the five aliens Aggregor kidnapped have powers based on the five elements: Water, Wind, Fire, Earth and Lightning.
 * Aggregor's name come from the word "aggregate," which means to form a collection from different parts, a very likely reference to his plan to absorb the full powers of the five aliens he captured and later his Ultimate Aggregor form. His name could also come from aggressor, another word for invader.
 * In the game Cartoon Network: Fusionfall there is a code set that comes with an Ultimate Aggregor Mask.
 * Ultimate Aggregor is the second villain to defeat an Ultimate, the first being Psyphon.
 * Aggregor is mentioned in Cosmic Destruction by Psyphon saying that he considered working for Aggregor but he preferred to work alone. Also in the same cutscene Psyphon said: "and look where it got him". However in order for this to work, the game's events would have to take place after Absolute Power.
 * Ultimate Kevin reverted the mutation of Aggregor, despite that Osmosians can only absorb 1/10th of the abilities of an alien (regardless of how much energy and DNA they absorb from that being), whereas Ultimate Aggregor had 10/10ths of power of the five Andromeda aliens. According to Dwayne, because he used a machine to turn them into pure energy, allowing him to gain the full power of the aliens and Ultimate Kevin absorbed this energy.
 * Aggregor's Toon Cricket Team's name is Aggregor Aggressives.
 * In his first appearance, Aggregor had six horns; In all his other appearances, he had only four.
 * According to the late Dwayne McDuffie, Aggregor knows about the Forge of Creation through studying legends for his entire life.