Ben Tennyson, Jake Long and Danny Phantom must combine forces when they face a fusion form of Kevin 11, Vlad Plasmius and the Huntsman.
- Ben Tennyson (Tara Strong) - the protagonist, encounters Jake and Danny during a Olympics event.
- Jake Long (Dante Basco) - the deuteragonist, shares a lot in common with Ben, due to grandfathers supporting them
- Danny Phantom (David Kaufman) - the tritagonist, who relates with Time Travelers since he was sent to prevent a certain chaos from occurring.
- Ben 10:
- Gwen Tennyson (Megan Smith) - prevents an ugly version of her (Alien Force, Ultimate Alien, and Omniverse) from stealing her life.
- Grandpa Max (Paul Eiding) - knows Lao Shi back in 1985, when he met his daughter, but did not tolerate his arrogance.
- Azmuth (Robert David Hall) - informs Ben that he must prevent the Robot from being active.
- Tetrax Shard (Dave Fennoy) - serves as an escort for Azmuth.
- American Dragon: Jake Long:
- Susan Long (Lauren Tom) - befriends Maddie and is more of a model for Gwen.
- Jonathan Long (Jeff Bennett) - revealed to be a Clown who Lao Shi frowns on.
- Hayley Long (Amy Bruckner) - gets spanked by Max for making fun of his Trailer.
- Arthur "Spud" Spudinski (Charlie Finn) - befriends Azmuth.
- Trixie Carter (Kittie) - has a crush on Tucker.
- Rose/Huntsgirl (Mae Whitman) - goes out for revenge on Huntsman.
- Grandpa Lao Shi (Keone Young) - remembers Max in 1985 battling a Gwlligy in Wales.
- Fu Dog (John DiMaggio) - reveals that Wildmutt is more Whale than dog.
- Danny Phantom:
- Tucker Foley (Rickey D'Shon Collins) - realizes that Trixie has a crush on him.
- Sam Manson (Grey Griffin) - helps Gwen with her powers.
- Jazz Fenton (Colleen O'Shaughnessey) - starts dressing like Paulina after a dare.
- Maddie Fenton (Kath Saucie) - befriends Susan, and relates having a lot of "Junk in the Trunk".
- Jack Fenton (Rob Paulson) - remembers Max revealing he was also in the Plumbers in the "Slaugh Unit".
- Negative 10: the secondary antagonists, a newer incarnation
- Vilgax (Steve Blum) - the new leader, remember's Jack for his interference.
- Dr. Animo (Dwight Schultz) - serves as his lieutenant.
- Penelope Spectra (Tara Strong) — possesses Gwen and matures her body into her's to live again.
- Charmcaster (Kari Wahlgren) - serves as Penelope's partner and later realizes her pregnancy and tutors Gwen to be her successor.
- Eli Pandaras (Jonathan Freeman) - acts as Huntsman's herald.
- Skulker (Kevin Michael Richardson) - serves as Vilgax's bodyguard.
- Desiree (Peri Gilpin) - acts as the sentry.
- Driscoll (Richard Doyle) - revealed to be an android.
- Kevin Plasmius the Huntsman/Dark Dragon (Arnold Vosloo/Clancy Brown) - the main antagonist, a fusion of Kevin 11 (Charlie Schlatter), Vlad Plasmius (Martin Mull) and the Huntsman (Jeff Bennett), his appearance consists of Huntsman's helmet and cloak, Vlad's costume, and Kevin's face and body, his goal is to get revenge for his alternate universe being undone. Near the end, the Dark Dragon was revealed to be his dragon form, as he was pretending to be Dark Dragon to infiltrate the Negative 10 so he ???
- Technus (Rob Paulson) - acts as the hacker.
- Heatblast (Steve Blum) - used to ???
- Wildmutt/Wildwhale (Dee Bradley Baker) - used to ???
- Diamondhead (Jim Ward) - used to ???
- XLR8 (Jim Ward) - used to ???
- Grey Matter (Richard Steven Horvitz) - used to ???
- Four Arms (Richard McGonagle) - used to ???
- Stinkfly (Dee Bradley Baker) - used to ???
- Ripjaws (Fred Tatasciore) - used to ???
- Upgrade (Tara Strong) - used to ???
- Ghostfreak (Steve Blum) - used to ???
- The animation for American Dragon: Jake Long in the special is the ??? version.
- Kevin Plasmius the Huntsman wasn't seen in the trailers, only as the Dark Dragon, but after Vilgax was defeated, the Dark Dragon revealed his true form.