Ben 10,000 (Original)

Ben Tennyson, nicknamed "Ben 10,000" is the fully grown Ben, from an alternate timeline.

Ben 10,000 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 is recognized everywhere as Ben 10,000, no matter what alien form he is using (because his aliens have an Omnitrix symbol).

His nickname comes from the fact that now Ben has access to at least 10,000 alien forms (he says he stopped counting), he also has unlocked the Omnitrix's Master Control, allowing Ben 10,000 to switch forms at will, without timing out.

Original Series
Having been fighting crime for such a long time, Ben 10,000 has grown into a strict and serious character, stopping 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 (according to a pop-up, this happened when Ben 10,000 was 15), though his interaction with his younger self causes him to lighten up somewhat, renaming his aliens. 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.

It was shown that Ben 10,000 has a son named Kenny (after Ben's cousin Ken) and a daughter named Gwendolyn(after Gwen). On Kenny's 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 has the Master Control locked.) The aliens he gave Ken were Spitter, Buzzshock, Shellhead, Ditto, Wildvine, Stinkfly, Toepick, XLR8, Sandbox and Snakepit. However, Toepick was later exchanged for Grey Matter because Kenny said that Toepick grosses him out.

Ultimate Alien
Ben 10,000 was mentioned by the other Ben 10,000 in Ben 10,000 Returns when Paradox mentioned that they traveled into crosstime.

Omniverse
In Ben Again an older Ben 10,000 came to Ben's time zone looking for Professor Paradox and to ask the present Ben for directions. On a dangerous situation, the Chronosapiens gone rogue and became temporal beasts they caused an dimensional rampage, causing the time war to start getting out of hand.

Ben 10

 * Ben 10,000 (first appearance)
 * Ken 10

​Ben 10: Omniverse

 * Ben Again (first re-appearance)

Aliens Used

 * XLR8
 * Four Arms
 * Spitter
 * Diamondhead
 * Buzzshock
 * Cannonbolt
 * Wildmutt
 * Heatblast
 * Stinkfly
 * Articguana
 * Benmummy
 * Way Big

Trivia

 * Ben 10,000 appears to favour XLR8 over any other aliens.
 * Ben 10,000 told the younger Ben that he would learn that being hero isn't all fun and games. This suggest that Ben 10,000 had experienced some event that caused him to take his hero duties more seriously. The enhanced version of the episode Ben 10,000 reveals that the events that happened when Ben 10,000 was 15 is what caused him to lose his joy of being a hero.
 * Ben 10,000 unlocked the Master Control. It is unknown if he is aware of how many aliens are in the Codon Stream or if he has only used 10,000 of the possible 1,000,910.