Highbreed

The Highbreed or Atasians are a powerful, and intelligent alien species. They were the main antagonists in the first two season of Ben 10: Alien Force.

Atasian
Atasians are an alien species of from planet Augstaka. Augstaka is a regal, welcome-looking planet that, believed by its inhabitants, is the center of the universe ("As it should be!", according to the Atasians). It has low-rolling green hills, regal coastlines, and clean, busy metropolises. Though it looks inviting, no species but the planet's own is allowed to set foot here.

The Atasians are a powerful, intelligent alien species, who are racist to the extent they believe that their DNA is the purest of all alien species and seek to cleanse the galaxy of "lower life forms". To achieve this, they sent advance forces of Highbreed and Xenocytes (parasitic facehugger-like aliens that possess the native species (DNAliens). These advance forces built massive teleporter gates in secret, through which the main Highbreed armada arrives and destroys the natives. The Atasians call themselves the Highbreed, because they despise every other sapient species and believing that they are above them. They also believe they are the first species ever to come into existence, but that is not be true because there are races that are old as the universe itself. The Atasians believe that their DNA is the purest of all alien species which in theoretically is seeing as they have maintained their blood purity for so long it has lead to much inbreeding. This idea of racial purity has become their undoing, because of lack of genetic diversity in the Atasian’s gene pool has lead that Atasian’s immune system has weakened, making them vulnerable to infection including disease and finally sterility; their entire race has rendered completely sterile and without children the Atasians as a species are as good as extinct. The Atasians were dying out but didn't wish to do so alone, spurring their xenocidal rampage throughout the universe to extreme levels. They wanted to take the rest of the universe with them by driving any sapient species they find or encountered to brink extinction like they are.

War of the Worlds and the aftermath
In War of the Worlds: Part 2, it was ascertained that the Highbreed's idea of racial purity lead to inbreeding, a loss of resistance to disease and finally sterility. The Highbreed were dying out but didn't wish to do so alone, spurring their xenocidal rampage throughout the universe. So, Ben used the Omnitrix to reconstruct the DNA of all Highbreeds with the DNA of the aliens in the Omnitrix, still unable to believe that their DNA is not "pure" anymore. Reinrassic III then appears and convinces them that Ben helped them live again. The council then elects Reinrassic III as the new Highbreed Supreme. Afterwards, he declares that the war is over.

It was also revealed in War of the Worlds, that the Highbreed DNA is encrypted in the Omnitrix, hinting that Ben could transform into a Highbreed if he were to unlock the master control again. He could also be the only "pure" Highbreed left.

In Vreedle, Vreedle, a red and blue Highbreed was revealed to be working for the High Court on Coda Coda.

In If All Else Fails, a hibernating Highbreed officer is awakened by an earthquake. Believing his race had lost the war, he activates a Highbreed back-up plan which activates seeds previously implanted into unknowing humans, including Max Tennyson. These infected humans gather together to form a giant Highbreed Tree Monster (a plant-monster that resembles a Highbreed) to destroy the humans. Unable to stop the bio-weapon on their own, Ben plans to enlist the help of Highbreed Supreme, Reinrassic III to put stop to the rogue Highbreed's plan. The army attempts to prevent the monster from destroying a nearby Twin Mesa Nuclear Power Plant, but the rogue Highbreed Officer stands in their way. Ben appears riding Ship with Reinrassic onboard. The Highbreed questions Reinrassic about his impurity so he opens his right hand, revealing the Imperial Seal. Recognizing Reinrassic as the Highbreed Supreme, the officer reveals that once activated the fail safe cannot be stopped. Reinrassic explains that they had implanted post-hypnotic seeds inside of a dozen or so humans who had been their prisoners. The Failsafe needs a large power source and upon absorbing the energy it needs it will explode and the resulting fallout would destroy the planet in minutes. Ben, Kevin, and Gwen enter the monster and fight their way to the its brain freeing the infected humans along the way. They discover that Grandpa Max is being used as its brain. Using Swampfire, Ben frees Grandpa Max causing the monster to stop moving. The Highbreed officer appears and takes control of it to prevent it from crashing the power plant with its weight. Ben, Gwen, Kevin and Grandpa Max escape unharmed but are saddened by the Highbreed officer's sacrifice. Reinrassic states he was "a soldier, doing his duty", and that their is no higher honor for a Highbreed. Gwen asks Reinrassic if their are any other Highbreed doomsday weapons still on Earth, he states their are none, but states he will check the records (revealing the possibility there are weapons and plans he even he doesn't know about). This may mean that there are still Highbreed weapons, technology, and plans still hidden on Earth.

It is shown in War of the Worlds: Part 2 that the Omnitrix/Ultimatrix contains Highbreed DNA, though Ben has yet to access this form. However, he is not in the Ben 10: Ultimate Alien opening.

Weaknesses
Due to their planet being cold, they have difficulties to survive and operate in warm climates, which cause them to quickly dehydrate if they do not find water.

Ben 10: Alien Force

 * Ben 10 Returns: Part 1 / Ben 10 Returns: Part 2
 * Max Out
 * Darkstar Rising
 * Alone Together
 * Undercover
 * Grounded
 * Inside Man
 * Birds of a Feather
 * War of the Worlds:Part 1 / War of the Worlds:Part 2
 * Vreedle, Vreedle
 * If All Else Fails

Ben 10: Ultimate Alien

 * Fame (news footage)

Notable Highbreeds

 * Reinrassic III
 * Highbreed Supreme
 * High Court's Officer

Trivia

 * Ironically, their names sound similar to "Hybrid", a mix between two different species, despite caring greatly about their so-called "purity". Although, it could foreshadow their DNA being mixed with other species' later on.