Negative 10

The Negative Ten was a mercenary team of antagonists who attacked Max, Gwen, Ben, and Cooper, a child who was being babysat by Grandpa Max for another Plumber.

They appeared in the two-part episode, Ben 10 vs. the Negative 10. They were led by Driscoll, a former Plumber who was dismissed and became the Forever King, leader of the Forever Knights.

The Negative Ten included nearly every main villain except Vilgax and Kevin Levin (who were trapped in the Null Void in the season two finale), Ghostfreak (who was re trapped in the Omnitrix), Hex (who became an infant), and Zombozo (who was possibly in a mental institution after getting scared from Ghostfreak).

Original Series

 * Driscoll (leader)
 * The Red Knight (second-in-command)
 * Dr. Animo
 * Charmcaster
 * Clancy
 * Rojo
 * Sublimino
 * Thumbskull
 * Acid Breath
 * Frightwig

Ultimate Alien

 * Villgax (leader)
 * Psyphon (second-in-command)
 * Albedo
 * Kolar
 * Overlord
 * Sevenseven
 * Sunny
 * Antonio
 * Ssserpent
 * Dr. Animo

Trivia
The Negative 10 are similar to the Spider-Man villain team the Sinister Six. Just like the Sinister Six being a group of Spider-Man villains desiring revenge against the wall-crawler, the Negative 10 is a villain team composed of villains Ben Tennyson has fought that has been brought together so all of them could have a chance to defeat him.

It seems that the another Negative 10 appeared in Hit 'Em Where They Live because Max said that he already took care of seven of the enemies after Ben's family plus Vulkanus, Zombozo and Charmcaster (and Sevenseven).