The Avengers: Earth's Mightiest Heroes!

The Avengers: Earth's Mightiest Heroes aired in October 20, 2010, and ended in March 24, 2013.

Season 1:
As the world's most dangerous super-villains break out of the Vault, the Cube, the Big House, and the Raft, five of Earth's mightiest heroes assemble a crime fighting alliance called the Avengers. The Avengers team includes Iron Man as team leader, Ant-Man, Thor, The Hulk, and The Wasp. Captain America, Black Panther, and Hawkeye have since joined the roster. When it comes to the Season Finale, it was revealed that Thor's brother Loki was responsible for the breakouts and having Enchantress form the Masters of Evil.

Season 2:
Season Two will depict the Avengers as they track down the remaining members of the Masters of Evil and end up getting involved in the upcoming war between the Kree and the Skrull. The Avengers are unaware that Captain America has been replaced by a Skrull. Ms. Marvel, Vision, Falcon, and Mockingbird will join the Avengers. Many other characters from the Marvel Universe such as Doctor Doom, Surtur, Thunderbolt Ross' Red Hulk form, and Guardians of the Galaxy have been confirmed to make appearances. Series producers Joshua Fine and Christopher Yost have revealed that certain returning characters will adapt their Ultimate Universe counterpart costumes, such as Director Fury who returns in Season 2 appearing more like the Ultimate Universe Fury with a shaved head and goatee and the Skrull who replaced Captain America will wear the costume directly adapted from Ultimate Captain America and will use an energy shield.

Season 3:
The Avengers must prove they can deal with Thanos! Due to Thanos murdering, the season will have a darker tone, Captain America wears his Commander America uniform from Steve Rogers: The Erskine Legacy, Ms. Marvel's costume now shows her bare midrift, and she has shorter hair and ever since Iron Man is Born, Lt. Col. Rhodes and the army have been trying to discover who built Ultimo,

The Avengers:

 * Captain America (Brian Bloom) - the new leader of the Avengers in "Code Red" and season 3
 * Tony Stark/Iron Man (Eric Loomis) - leader in seasons 1-2, later second-in-command in season 3, and leader of the Illuminati
 * Hulk (Gabriel Mann/Fred Tatasciore)
 * Hank Pym/Ant-Man/Yellowjacket (Wally Wingert) - became Yellowjacket in "Yellowjacket"
 * Thor (Rick D. Wasserman) -
 * Wasp (Colleen O'Shaughnessey) -
 * T'Challa/Black Panther (James C. Mathis III)
 * Clint Barton/Hawkeye (Chris Cox)
 * Ms. Marvel (Jennifer Hale) -
 * Vision (Peter Jessop) -
 * Spider-Man (Drake Bell, Josh Keaton for Season 3) - appears as a reservist member
 * Falcon (Lance Reddick) - joins the Avengers after stopping Galactus
 * Black Widow (Vanessa Marshall) - joins the Avengers after stopping Galactus
 * Mockingbird (Elizabeth Daily)
 * Greer Grant/ Hellcat/ Tigra (Ashley Beill)

Inhumans:

 * Black Bolt
 * Medusa (Grey DeLisle)
 * Karnak (Steven Blum)
 * Gorgon (Greg Eagles)
 * Triton (Richard Green)
 * Crystal (Kim Mai Guest)
 * Maximus the Mad (Troy Baker)
 * Lockjaw (Dee Bradley Baker)
 * Sentry 219 (Mark Hamill)

Fantastic Four:

 * Mr. Fantastic (Dee Bradley Baker)
 * Invisible Woman (Erin Torpey)
 * Human Torch (David Kaufman)
 * Thing (Clancy Brown)

X-Men:

 * Professor Charles Xavier (Jim Ward)
 * Cyclops (Nolan North)
 * Jean Grey (Jennifer Hale)
 * Wolverine (Steve Blum)
 * Colossus (Phil Morris)
 * Storm (Susan Dalian)
 * Thunderbird (Michael Horse)
 * Banshee (Nick Chunlind)
 * Kitty Pryde (Tara Strong)
 * Doctor Strange (Xander Berkley)
 * Namor (James Patrick Stewart)

S.H.I.E.L.D.:

 * Nick Fury (Alex Desert)
 * Black Widow (Vanessa Marshall)
 * Quake (Lacey Chalbert)
 * Maria Hill (Kari Wuhrer)
 * Clay Quartermain (Troy Baker)
 * Jimmy Woo (Nolan North)
 * Jasper Sitwell (Tom Kane)
 * Phil Coulson (Clark Gregg)

Allies:

 * Pepper Potts (Dawn Oliveri) -
 * Balder (Nolan North)
 * Captain Mar-Vell (Roger Craig Smith)
 * Sword:
 * Abigail Brand (Mary Elizabeth McGlynn)
 * Sydren (Troy Baker)
 * Henry Gyrich (Jim Ward)
 * Luke Cage (Christopher B. Duncan) 
 * Iron Fist (Loren Lester)
 * Scott Lang/Ant-Man (Crispin Freeman)
 * Cassandra Lang (Colleen O'Shaughnessey)
 * Guardians of the Galaxy:
 * Star-Lord (Steve Downes)
 * Adam Warlock (Kirk Thornton)
 * Groot (Troy Baker)
 * Rocket Raccoon (Greg Ellis)
 * Quasar (Moira Quirk)
 * Carina Korvac (Jennifer Hale)
 * Beta Ray Bill (Steven Blum)
 * Lady Sif (Nika Futterman)
 * Jane Foster (Kari Wahlgren)
 * Winter Soldier (Jon Curry)
 * Tyrone "Ty" Johnson/Cloak (Khary Payton)
 * Doc Samson (Cam Clarke)
 * Odin (Corey Burton ) - retakes his place after Kurse Posed as him.
 * Silver Surfer (Yuri Lowenthal)
 * Mary Jane Watson (Alyssa Milano)
 * 3-D Man (???)
 * Machine Man (???)
 * Bill Foster/Giant-Man II (???)
 * Uatu the Watcher (???)
 * Sasquatch
 * Omega the Unknown (???)
 * Rom the Space Warrior (???)
 * Morbius (???)
 * Crystar (???)
 * Human Fly (???) - a fellow circus performer of Hawkeye's

Season 1:

 * Loki (Graham McTavish) - the main antagonist, was the cause of the Breakouts, and had the Enchantress form the Masters of Evil
 * Baron Strucker (Jim Ward) - One of the key villains of Season 1
 * Ultron (Tom Kane) - One of the key villains of Season 1
 * M.O.D.O.C. (Wally Wingert) - One of the key villains of Season 1
 * Kang the Conqueror (Jonathan Adams) - One of the key villains of Season 1
 * Leader (Jeffrey Combs) - One of the key villains of Season 1
 * The Masters of Evil:
 * Baron Zemo (Robin Atkin Downes) - revealed to be the son of Baron Zemo, and realizes the true potential and heart of Captain America and asks for a truce!
 * Enchantress (Kari Wahlgren)
 * Executioner (John DiMaggio)
 * Crimson Dynamo (Chris Cox)
 * Abombination (Robin Atkin Downes)
 * Wonder Man (Phil Lamaar)
 * Chemistro (Nolan North)
 * Living Laser (Nolan North)
 * Grey Gargoyle (Troy Baker)
 * Arnim Zola (Grant Moninger)

Season 2:

 * Kang the Conqueror (Jonathan Freeman) - he is the main antagonist of season 2, he escapes to stop the Avengers once again before they end up causing the destruction of his timeline by letting Black Panther live during the destruction of Earth's Sun by the Kree, after he was defeated by the New Avengers in "New Avengers", Spider-Man makes him go through the portal and is seen being chased by a Carnotaurus.
 * Red Skull (Steve Blum) - revealed to be alive, disguised as Dell Rusk, the head of the US Dept. of Security, to finally have his revenge on Captain America, defeated and was locked up in Prison 42.
 * Thaddeus Ross/Red Hulk (Keith Ferguson/Fred Tatasciore) - Ross is transformed into the Red Hulk by the Winter Soldier on orders from Red Hulk in order to finally have his revenge on Hulk.
 * A.I.M.:
 * Scientist Supreme (Nolan North)
 * Dr. Lyle Getz (Kyle Hebert)
 * Dr. Doom (Lex Lang) - One of the main antagonists in Season 2, remains at large
 * Surtur (Rick D. Wasserman) - one of the main antagonists in Season 2, remains at large
 * Enchantress (Kari Wahlgren) - trapped under Surtur's control, the Enchantress serves as the Dragon to the Fire Giant for Seasons 2
 * Ultron-7 (Tom Kane) - having rebuilt himself yet again following his destruction at the hands of Hank Pym.
 * Skrulls:
 * Veranke (Elizabeth Daily) - Queen of the Skrulls, and one of the main antagonists from Season 2.
 * Criti Noll (Brian Bloom) - The Captain America Imposter, and Veranke's second-in-command of the Skrull Fleet.
 * Super Skrull (Kyle Hebert) -Veranke's third-in-command of the Skrull Empire, and leader of the Super Skrull army.
 * Kree:
 * Kalum Lo (Fred Tatasciore)
 * Ronan the Accuser (Keith Szarabajka)
 * Sentry-459
 * Supreme Intelligence (David Kaye season 2, Dee Bradley Baker season 3)
 * Yon-Rogg (Fred Tatasciore)

Season 3:

 * Thanos (Michael Ironside) - the main antagonist, gone on a quest to search for the Infinity Gems. When he defeats his enemies, he snaps their necks, he also uses his powers to drain the victims's souls from their bodies and absorbs them into his being in order to amplify his powers. His victims will include the Guardians of the Galaxy, Supreme Intelligence, Veranke, Michael Korvac, and Yon-Rogg. His goals are to kill everyone and become a god, his hobby include killing and playing god
 * Surtur (Rick D. Wasserman) - he plans to start Ragnarok by consuming the Sun Goddess and the Moon God, as it plunges Midgard and the Nine Realms into darkness
 * Doctor Doom (Mark Hamill) - ever since he was roomates with Reed Richards, he plans to ressurect his mother, Cynthia von Doom from the Realm of Mephisto
 * Magneto (Ron Perlman)
 * Mandarin (James Hong)

Other villains

 * Absorbing Man (Rick D. Wasserman)
 * Annihilus (Kevin Michael Richardson) - revealed to have made a deal with Kang to cause the attack on 42
 * Armadillo (Ogie Banks)
 * Baron Blood (Peter Stormare)
 * Bi-Beast (Wade Williams)
 * Blank (Richard McGonagle)
 * Blizzard (Troy Baker) - killed by the Annihilation Wave in "Assault on 42"
 * Buck Chisholm/Trickshot (Jim Meskimen) - Clint's mentor in archery
 * Circus of Crime:
 * Bruto the Strongman (Richard McGonagle)
 * Cannonball (J.B. Blanc)
 * Clown (Charlie Adler)
 * Fire-Eater (Ogie Banks)
 * Flying Gambonnos (Jeff Bennett and Maurice LaMarche)
 * Livewire (Cindy Robinson)
 * Princesss Python (Tara Strong)
 * Ringmaster (Corey Burton)
 * Crossfire (Neil Ross)
 * Deathlok (John DeLancie) - appears as a Hydra agent
 * Doctor Octopus (Corey Burton)
 * Erik Hellstrom (Robert Patrick)
 * Galactus (David Kaye)
 * Glenn Talbot (Troy Baker)
 * Graviton (Fred Tatasciore)
 * Griffin (Fred Tatasciore)
 * Heralds of Galactus
 * Air-Walker (Daniel Riordan)
 * Firelord (Khary Payton)
 * Stardust (Andrea Baker)
 * Terrax (Kevin Grevioux)
 * Impossible Man (Jeff Bennett)
 * Kurse (Clancy Brown) - posed as Odin in Season One, and 2 and released Surtur, was destroyed by Loki and Thor.
 * Lucia Von Bardas (Kirsten Potter)
 * Mad Thinker (Danny Mann)
 * Malekith (Quinton Flynn)
 * Mandrill (Fred Tatasciore)
 * Michael Korvac (Troy Baker)
 * Moltar (Peter MacNicol)
 * Purple Man (Brent Spiner)
 * Professor Thornton (Tom Kane)
 * Ravonna (Cindy Robinson)
 * Red Ghost
 * Serpent Society:
 * King Cobra (James C. Mathis III)
 * Anaconda (Vanessa Marshall)
 * Bushmaster (Phill LaMarr)
 * Constrictor (Cam Clarke in Season 1, Troy Baker in Season 2)
 * Death Adder (Dee Bradley Baker)
 * Rattler (Chris Cox)
 * Madame Viper (Vanessa Marshall)
 * Sinister Six:
 * Vulture (Corey Burton)
 * Electro (Crispin Glover)
 * Sandman (Wade Williams)
 * Mysterio (Kevin Michael Richardson)
 * Kraven the Hunter (Hector Elizondo)
 * Shuma Gorath (Dee Bradley Baker)
 * Swordsman (Jeffrey Tambor - using Crazy Quilt's tone)
 * Technovore (Dwight Schultz)
 * U-Foes:
 * Vector (Cam Clarke)
 * Ironclad (Kevin Michael Richardson)
 * Vapor (Colleen O'Shaughnessey)
 * X-Ray (Dee Bradley Baker)
 * Ultimo (Peter Stormare)
 * Whiplash (Tara Strong) - meets Venom, but refuses to join!
 * Wrecking Crew:
 * Wrecker (J.B. Blanc)
 * Bulldozer (James C. Mathis III)
 * Piledriver (Nolan North)
 * Thunderball (Gary Anthony Williams)
 * Zzzax (Dee Bradley Baker)