Agent Six has fully recovered. Caesar injects the Omega Nanite back into Rex and the film ends with Alpha, now in the Null Void, stirring within its prison of matter, hinting that it will return. Production Heroes United is the double-length third and fourth episodes of Generator Rexs third season. As it is set in Generator Rexs fictional universe and depicts Ben crossing over into it from his own world, Ben, his various aliens and other characters from Ben 10: Ultimate Alien appear in Generator Rexs art and animation style when in Rex's universe. Other main characters of Ultimate Alien such as Gwen Tennyson, Kevin Levin and Max Tennyson do not make a full physical appearance (but they are drawn in Generator Rex style), only to be seen in a flashback scene where Rex and Ben exchange backstories. Comics Only one comic is based on Ben 10 / Generator Rex: Heroes United, called Hero Times Two, has been released to continue the story-line and it centers around Rex going to Ben's dimension. Cast Daryl Sabara as Rex Salazar Yuri Lowenthal as Ben Tennyson, XLR8, Upgrade Wally Kurth as Agent Six Grey DeLisle as Rebecca Holiday, Diane Farrah, Young Woman John DiMaggio as Bobo Haha, Rath, Black Pawn J. K. Simmons as White Knight Michael Emerson as Alpha Jennifer Hale as Black Knight Freddy Rodriguez as Caesar Salazar Dee Bradley Baker as Humungousaur, Diamondhead, Lodestar, Big Chill, Four Arms, Cannonbolt, Upchuck David Kaye as Shocksquatch See also The Grim Adventures of the KND Cartoon Network: Punch Time Explosion References 2011 American television episodes Ben 10 mass media Crossover science fiction television episodes Generator Rex Television episodes about parallel universes Animated crossover television specials Animated films based on animated series