In the midst of the Marvel Cinematic Universe's Phase One, an animated series was created to capitalize on the hype of Marvel characters. The result was an animated show titled Avengers: Earth's Mightiest Heroes which doesn't get discussed much but boasts a 100% rating on Rotten Tomatoes.

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Sadly, the series only lasted two seasons before it was canceled as a result of Marvel being merged with Disney to be revived as the quasi-sequel series Avengers Assemble. The original run remains a fan favorite with plenty of highly rated episodes starring Marvel's iconic superheroes and villains.

The Man Who Stole Tomorrow (S1,E17)- 8.5

Kang The Conquerer showing the Avengers a vision of the future in Avengers: Earth's Mightiest Heroes

Before the Loki series introduced him, Avengers: Earth's Mightiest Heroes made the powerful Kang The Conqueror into the villain of a multi-episode saga. It started with The Man Who Stole Tomorrow, taking its time to establish the villain as a powerful and imposing force for the Avengers to battle.

What makes this episode stand out is how Kang operates. He doesn't just show up and begin fighting the Avengers; instead, he tries to reason with them by showing them their future of a destroyed Earth. Of course, the Avengers refuse which begins the war against Kang; showing that Kang is more than a mindless killer and believes he is helping the universe by conquering in the past.

The Kang Dynasty (S1,E19) - 8.5

The Avengers in their space suits in Avengers: Earth's Mightiest Heroes

In the final episode of the Kang saga, the Avengers use their new artificial intelligence Ultron to fight Kang aboard his own ship. It proves to be an action-packed climax with plenty of suspense however it threw in some twists and turns, continuing to show depth to the villainous Kang.

Similar to the Marvel Cinematic Universe, not only does it provide a thriller superhero story on its own but it sets up storylines for the future of the show. The biggest and most obvious one being Ultron, created by Ant-Man while Kang warns the Avengers about the Skrull invasion.

Ultron-5 (S1,E22) - 8.6

Wasp confronting Ultron in Avengers: Earth's Mightiest Heroes

Hank Pym AKA Ant-Man seems to have done too well in the creation of Ultron. He begins to agree that humanity is too violent and past the point of no return, so he rebels against the Avengers, commencing his plot to destroy all of humanity. This begins the Ultron saga of Earth's Mightiest Heroes.

Despite Ultron being in his earliest form, he proves to be an intimidating villain: emotionless and cold. He's able to catch Captain America's shield with ease and nearly kill all of the Avengers in different ways, only in one body. This makes it scary when the episode ends with Ultron's programming uploaded to the internet.

Avengers Assemble (S2,E26) - 8.7

All of the Avengers assembled in Avengers: Earth's Mightiest Heroes

This was the final episode of Earth's Mightiest Heroes before it was canceled and it features the Avengers battling the great Galactus alongside many heroes they've met in the past including Spider-Man, Wolverine, the Fantastic Four, and even the Heroes For Hire.

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This episode was to the animated series what Avengers: Endgame was to the MCU, the massive culmination of two seasons worth of build-up. Much like Endgame, it was quite the payoff with a plethora of action sequences and Galactus acting as the penultimate villain of this universe.

Who Do You Trust? (S2,E7) - 8.8

The Avengers showing mistrust in Hawkeye in Avengers: Earth's Mightiest Heroes

One of the largest sagas in Earth's Mightiest Heroes is the Skrull saga which began with "Who Do You Trust?" Embracing a claustrophobic thriller similar to John Carpenter's The Thing, this episode is praised for crafting suspense and paranoia as the Avengers try to figure out who in the team is a Skrull in perfect disguise.

Part of this comes from the voice actors who clearly understand their characters and give believable performances. On the first watch, it is genuinely hard to tell who is the Skrull and who is an Avenger due to the chaotic perspective.

Infiltration (S2,E11) - 8.8

Nick Fury and Quake investigating who is a doppleganger in Avengers: Earth's Mightiest Heroes

With Carol Danvers and the ever-ominous Doctor Doom returning as recurring characters, the Skrull saga continued with Iron Man trying to find a way to detect Skrulls. Carol Danvers' Ms. Marvel is taking the lead against the Skrull invasion while the Avengers turn out to all be Skrulls in disguise, trying to use their guises to get Vibranium for their invasion.

Like most episodes of the Skrull saga, Infiltration balances superhero action with surprisingly gripping drama as the heroes try to defeat the invaders using their intelligence. Doctor Doom makes for a welcome secondary villain, showing how expansive this animated universe was.

Secret Invasion (S2,E12) - 8.8

Captain America battling his Skrull doppleganger in Avengers: Earth's Mightiest Heroes

The full invasion of the Skrulls takes place and it turns into an all-out war between them and the Avengers. After several episodes of build-up and tension, Secret Invasion ends the Skrull saga with a much more action-packed climax.

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Secret Invasion showcases just how much of a threat the Skrulls are and why this saga was so beloved. It also serves as a payoff since the Skrulls had been promised since the Kang saga.

New Avengers (S2,E23) - 8.8

The New Avengers assembled in Avengers Earth's Mightiest Heroes

In a reverse scenario of Avengers: Endgame, all the original Avengers are gone thanks to the return of Kang The Conqueror and it's up to the newer characters to come together as a new team. This is due to an emergency protocol set up and executed by Iron Man before the Avengers are captured.

That alone is what makes the episode so beloved by fans: rather than the Avengers they are so used to, most of the episode focuses on Spider-Man, Wolverine in his classic yellow suit, War Machine, Ben Grimm, Luke Cage, and Iron Fist. The New Avengers were enjoyable with unique banter and action scenes that could have made for a spin-off series if the show hadn't been canceled.

Prisoner Of War (S2,E10) - 8.9

Captain America interrogating a Skrull in Avengers: Earth's Mightiest Heroes

During the Skrull saga, Captain America was taken prisoner by the invaders. Prisoner Of War showcases Cap's time as a prisoner and his escape alongside other unfortunate abductees, some of them even being villains from the past. Prisoner Of War is interesting because Captain America is the only Avenger present.

Typically, Earth's Mightiest Heroes juggles several plots in one episode but this one is mainly about Steve Rogers trying to escape. It's reminiscent of classic prison escape films. It makes the episode feel experimental, trying to be a genre piece rather than a normal superhero romp which is commendable.

A Day Unlike Any Other (S1,E26) - 9.0

The Avengers speaking with Odin on Asgard in Avengers: Earth's Mightiest Heroes

Much like the comics and the first Avengers movie, it is Thor's brother Loki that ends up being the big villain for the ending of season 1 of Earth's Mightiest Heroes. It continues the story from The Fall Of Asgard with Loki still on Odin's throne and the Avengers are separated across the Nine Realms.

With the other eight realms now destroyed, Midgard is all the remains and it's up to the Avengers to stop Loki. While Earth's Mightiest Heroes never shied from darker elements, this finale felt darker than both the Kang and Ultron sagas prior, feeling like an epic conclusion to the beloved first season with plenty of twists, turns, and giant action sequences.

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