Aggregor

Aggregor (voiced by John DiMaggio) is a villain in the new series, Ben 10: Ultimate Alien, an Osmosian (the same species as Ben's former nemesis and current best friend Kevin) warlord with lethal absorbing powers. He was introduced in Fame (though his nature was only truly explained in Escape From Aggregor), and serves as the main antagonist of the series so far. His objective is to absorb the abilities of various powerful aliens he captured from the Andromeda Galaxy in order to become strong enough to get what he calls the "Ultimate Prize".

Appearance
Aggregor's appearance is, for the most part, similar to that of a human. However, he has pink, pale skin and small horns coming out of his head. He has long black hair and red eyes. He wears a brown tunic and wields a spear-like weapon. In the episode Escape From Aggregor, his species is confirmed to be Osmosian.

Powers and Abilities
Being an Osmosian, Aggregor has the amazing ability to absorb matter and energy from anything in order to use it in various way. While Kevin currently relies more on his matter-absorbing powers (due to his lack of control of his powers when absorbing electricity and energy from living beings), Aggregor appears to have fully mastered his powers, and prefers absorbing energy from other life-forms, acquiring their powers and abilities but only at 1/10 of its strength. Unlike Kevin, however, the powers and abilities he absorbs don't drastically change his appearance (most likely because of his advanced age considering that Kevin was able to do the same in Ken 10) : for example, when he absorbed powers from one of Galapagus' friends, his appearance stayed the same, though he could now grow six hollow ports on his torso to create wind attacks or fly at will. Also, while Kevin, when he absorbed powers from the Omnitrix aliens, left them unharmed (but could only use them temporarily if he had absorbed their life force with their powers he might have had more control), Aggregor absorbs all of the energy from living beings, including their life force, leaving nothing else from them than a horrific skeleton-like dead body. Just like Kevin, he needs physical contact with the creature or the object to absorb its energy.

In addition to his matter and energy-absorbing powers, Aggregor is a highly skilled hand-to-hand fighter, and relies on a spear-like weapon which can be used to stab em or blast his enemies by shooting a red lightning-like energy blast that he uses to shock or electrify opponents. At one point, he also used his spear-like weapon to display unusually strong telekinetic powers and abilities, enabling him to lift and levitate objects and people at will surrounded in a telekinetic aura (very similer to Brainstorm's abilities) which is the same whitish red lightning-like energy from his spear. As shown in the episode "Andreas’ Fault", Agreggor can summon his spaceship with his spear-like weapon. As shown in "Fused" when he used it against Brainstorm, the weapon is designed to combat creatures that control and manipulate electricity.

Much like Ben's archenemy Vilgax, he uses robot drones as his army rather than living soldiers, though his robots are more humanoid in shape and stature than Vilgax's. However, despite having this army under his command, he's shown to prefer do the job himself rather than letting them handle the task (which was the weakness Ben had exploited against the Highbreed). He has captured and later re-captured the five Andromeda aliens by himself, and didn't even mind to once disguise himself as a Plumber to do it.

Ultimate Alien
In the series premiere, Fame, after Bivalvan was defeated by Ultimate Spidermonkey, 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, having found him somehow. His first line was "No one escapes me, Bivalvan". Bivalvan is then heard screaming offscreen as Aggregor tortures him before taking him away.

He appeared again in Escape From Aggregor, where Galapagus told the tale of how he and the other four aliens were captured and escaped. Aggregor revealed that his plan was to absorb the full powers and abilities of the five aliens he captured using a machine he had built back on his home planet and make himself invincible so he can obtain the "ultimate prize". At the end of the episode when Ben and the others sent Galapagus back to his home world, the Plumber agent that was transporting him is revealed to be actually Aggregor in disguise.

He appeared again at the end of Too Hot To Handle after Ben, Gwen, and Kevin succeeded in subduing P'andor and had him taken off the planet. The Osmosian 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.

He then appeared at the end of Andreas’ Fault, where he 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 "The fun can begin".

Ben, Gwen and Kevin finally met him face to face in Fused, where it was revealed by Ra'ad that Aggregor was using the signal of the Ultimatrix to locate the aliens. The Amperi then 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, Kevin attempted to fight him, being an Osmosian like him, but Aggregor replied that Kevin wasn't even close to being an Osmosian like him as he easily knocked Kevin away. When Ben transformed into Ra'ad's form (which he named AmpFibian ), Aggregor decided that he could do just as well for his plans. Fortunately, Gwen used a teleportation spell to transport the trio to Kevin's warehouse. Aggregor returned to his ship to have 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's spear weapon neutralized Brainstorm's yellow lightning attacks and easily defeated him. Aggregor then attempted to use the Ultimatrix to forcibly (and extremely painfully) change Ben back into Ampfibian for his plan almost fatally killing him in the process, but Ra'ad (having been given a lecture by Kevin) returned to save Ben. In the clash between Ra'ad's whitish blue lightning attacks and the whitish red energy blast of Aggregor's weapon, 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 and save them.

Appearances

 * Fame
 * Escape From Aggregor
 * Too Hot To Handle
 * Andreas’ Fault
 * Fused

Trivia

 * Aggregor's appearance is very similar to a Zabrak (more specifically Eeth Koth, Agen Kolar, and Darth Maul) from Star Wars. It is possible Aggregor's appearance is based on a Zabrak.
 * According to Dwayne McDuffie, Aggregor is a greater threat than Vilgax.
 * It was revealed in a book called Ben 10 Ultimate Alien: Complete Guide, which Aggregor will get to absorb the powers Ultimate_Aggregor.JPG Bivalvan, Galapagos, P'andor, Andreas, and Ra'ad, and turn into a monster like Kevin in Ben 10 and Season 3 of Alien Force, staying with his original face, his hair like the tentacles of Ra'ad, gray neck with three slots of P'andor, Andreas's arms, Galapago's holes in the chest, and Bivalvan's legs.
 * Aggregor refers to Kevin, a fellow Osmosian, as a 'hatchling'. a reference to their difference in age, power, and experience.
 * Unlike all of Ben's previous enemies, Aggregor has defeated the trio all at once in a few minutes, which makes him the most dangerous enemy they have faced.
 * 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 any known rank (even subdue 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.
 * He is the first full Osmosian villain as Kevin is only part-Osmosian.
 * It is unknown if Aggregor and Kevin's father, Devin Levin have any connection other than their both being Osmosians. It is unknown if they are related or even knew each other (if they knew each other it is unknown if they were casual aquaintences, friends, and/or enemies).
 * It is interesting to note that the five aliens he kidnapped have powers/appearances based on the five elements (Water, Wind, Fire, Earth, and Lightning), which may have something to do with him wanting their powers.
 * Aggregor's plan to absorb all the powers and abilities of the five Andromeda aliens is similar to Kevin's plan in the original series to obtain the powers of all of Ben's original ten alien forms (which unfortunately had disastrous results). As Aggregor has at least 89 more years of experience, it is unlikely that his transformation will be similar.
 * His 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.
 * He seems very dependent on his spear, using it in almost every fight and quickly panicked and attempted to use it to defend himself when Brainstorm attacked him, and he had a shocked/scared expression on his face as this was happening.
 * Aggregor said in Fused that his spear was design to face electromanipulative species. Some rumors says that after Aggregor had a shocked/scared expression on his face as this was happening.
 * Some rumors says that after Aggregor absorbed all their powers he will become Ultimate Aggregor
 * Aggregor has a similar appearance of that of Generator Rex's villian, Van Kliess.