Ben 10,000 (Original)

Ben Tennyson, nicknamed "Ben 10,000" is the fully grown Ben Tennyson, twenty years into the future, who has become a well known "super hero" in his own right. He seems to not have the same ability to come up with names for his aliens off the spot like when he was 10.

Twenty years into the future, Ben has become a full-time hero. He is tall, more muscular, and sports a full-beard. The Omnitrix has also changed in appearance, becoming bulkier and more gauntlet-like in shape. He no longer needs to conceal his identity and is recognized everywhere as Ben 10,000, no matter what alien form he is using (obviously because he has an Omnitrix/Ultimatrix symbol on his chest in alien form). The name comes from the fact that now Ben has access to 10,000 alien forms, he also has unlocked the Omnitrix's master control function, allowing him to switch forms at will, without timing out.

Ben 10
Having been fighting crime for such a long time, Ben has grown into a more strict and serious character, going so far as to stop naming his aliens (which the present Ben considers "half the fun" of using them), and has a darker way of dealing with villains, such as defeating Vilgax by literally mutilating him, though his interaction with his past self causes him to lighten up somewhat, naming his aliens all over again. Ben's alien forms have aged with him, which is evident in their appearances and abilities. For example, Ben 10,000's XLR8 is noticeably taller with gray outlines in place of the ordinary blue, as well as being considerably faster. (Ben 10,000)

Twelve years later it was shown that Ben has a son named Kenny Tennyson (after Ben's cousin Ken). On his tenth birthday he gives him an Omnitrix like the one he had in the original series (like his first one, only he has 10 accessible aliens and times out). The aliens he gave Ken were Spitter, Buzzshock, Shellhead, Ditto, Wildvine, Stinkfly, Toepick, XLR8, Sandbox and Snakepit. It was also revealed he has a daughter named Gwendolyn Tennyson (after his cousin Gwen), who could be the girl that gave Ken a present at Kenny's birthday party. (Ken 10)

Ben 10: Ultimate Alien
Ben 10,000 in a alternate form appeared in the Ultimate Alien episode Ben 10,000 Returns. He asks Ben, Gwen and Kevin for help in stopping Eon (who also returns in this episode).

Since Ben now has the Ultimatrix, and is older, Ben 10,000 looks different. The symbol used for Ultimate forms is also there on his chest.

Aliens Used

 * XLR8
 * Four Arms
 * Spitter
 * Diamondhead
 * Buzzshock
 * Cannonbolt
 * Wildmutt
 * Heatblast
 * Stinkfly
 * Articguana
 * Benmummy
 * Way Big
 * Eye Guy
 * Grey Matter

Trivia

 * Since Ben did not take off the Omnitrix, it did not recalibrate, instead upgrading itself into a new form while still giving Ben access to his original aliens. He would've unlocked the Master Control again after continued use and learned how to use it effectively, defeating enemies with ease. Because of this he did not need to form a team in the alternate Alien Force timeline so Gwen does not learn she's an Anodite (resulting in still using spells instead of mana, eventually using the Keystone of Bezel to recreate The Charms of Bezel becoming the future Gwen, Gwendolyn), Kevin still being enemies with Ben, Azmuth not building the Ultimatrix, and Ben not getting access to the Alien Force Aliens.
 * Ben 10,000 went through several changes before his finished design; a far more muscular and slender than the previous models used.
 * Ben 10,000's appearence resembles Obi-Wan-Kenobi in Episode III Revenge of the Sith in the Star Wars Saga.
 * Ben 10,000 has a darker way defeating his enemies. For example mutilating Vilgax.