Fantastic Four: World's Greatest Heroes - Season 1 - Eps 8: Imperius Rex
Namor the Sub-Mariner arrives with a decree banning humankind from the oceans. Susan and Johnny go underwater to negotiate, but are taken prisoner in Atlantis. Ben and Reed must fight their way through sea monsters and Namor to save their teammates.
About Fantastic Four: World's Greatest Heroes

Title: Fantastic Four: World's Greatest Heroes
First Air Date: 2006-09-02
Last Air Date: 2007-10-20
Status: Ended
Rating: 7.5/10 (from 89 votes)
Language: EN
Seasons: 2
Total Episodes: 26
Network: Cartoon Network
Genres: Animation, Action & Adventure, Sci-Fi & Fantasy, Kids
Production Companies: MoonScoop, Marvel Entertainment
Synopsis
Mr. Fantastic, the Invisible Woman, the Human Torch, and the Thing battle some of their greatest foes, including Doctor Doom, Ronan the Accuser, the Multiple Man, and Mole Man.
Cast

Hiro Kanagawa
Mr. Fantastic (voice)

Lara Gilchrist
Invisible Woman (voice)

Christopher Jacot
Johnny Storm (voice)

Brian Dobson
Ben Grimm (voice)