Fans are excitedly awaiting the official debut of the newest Avengers villain to join the Marvel Cinematic Universe. Kang the Conqueror was first teased in Loki as He Who Remains. This only hyped up fans for Jonathan Majors’ performance in the role of the time-traveling warrior with a grudge against the Avengers.

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Of course, Kang is just one of a few iconic Avengers villains who have made the jump to the big screen over the years. Villains Like Thanos and Ultron all threatened to destroy Earth’s mightiest heroes. There are quite a few memorable villains of the Avengers who continue to threaten the team in the comics that have become known as their most iconic enemies.

10 Loki Is A Powerful Asgardian Whose Scheme Against His Brother Thor Formed The Avengers

Loki with Mjolnir on the Brooklyn Bridge in Marvel Comics

The Avengers might have never formed together if it wasn’t for the Asgardian trickster Loki. In one of Loki's best comic storylines, the God of Mischief manipulated the gamma-powered Hulk in a scheme against his brother Thor. Hulk's ensuing rampage caught the attention of other heroes like Iron Man, Ant-Man and The Wasp, who soon banded together in an effort to defeat Loki.

Since that fateful moment, Loki has returned time and again to threaten the Avengers in his ongoing feud with his brother Thor. Loki never really learned his lesson, as he has purposefully or inadvertently formed other teams of Avengers over the years. Loki has also proven his mischievous nature by manipulating events like Siege from behind the scenes.

9 The Masters Of Evil Were Formed By Baron Zemo To Take On Captain America And The Avengers

Baron Zemo and the Masters of Evil in Marvel Comics

Captain America wasn’t one of the first Avengers, though he did join the team shortly after to become one of their founding members. This has brought some heat down on the team over the years due to their connection to the Sentinel of Liberty. Once Captain America’s old enemy Baron Zemo discovered he had joined the Avengers, he created his own team of villains.

The Masters of Evil started off small and didn’t pose that great of a threat to the Avengers, though the team has continued to grow under new leaders over the years. When the original Zemo died, his son took over and assembled one of the best Masters of Evil line-ups for an assault on Avengers Mansion that devastated the team.

8 Count Nefaria Is An Ionic Being And One Of The Strongest Foes The Avengers Have Ever Faced

Count Nefaria fighting the Avengers in Marvel Comics

Originally a powerful crime boss in the Maggia, Count Nefaria eventually gained incredible powers thanks to the ionic machine that empowered other characters like Wonder Man and Atlas. Count Nefaria was given the incredibly amplified powers of the Living Laser, Power Man (Atlas’ former identity) and Whirlwind.

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The ionic process made him both incredibly fast and strong, while also giving him the ability to project powerful blasts of energy. Count Nefaria was able to take on entire rosters of Avengers at the same time, and he continued to threaten the team long after his apparent death. Nefaria also gained the ability to control other ionic beings, which almost made him unstoppable.

7 The Supreme Intelligence Of The Kree Has Frequently Threatened To Destroy Or Takeover Earth

Marvel's Kree Supreme Intelligence

The Avengers have dealt with a number of extraterrestrial threats to Earth over the years. The Kree have an incredibly long history with the Avengers. The Kree are usually ruled by an artificial being known as the Supreme Intelligence, which is composed of the greatest Kree minds. Some of the worst things the Kree Supreme Intelligence has done heavily impacted the Avengers.

The heroes of Earth have been involved in a number of skirmishes like the “Kree-Skrull War” and the Kree-Shi’ar war from “Operation: Galactic Storm.”. The Avengers have also welcomed a few Kree heroes onto the team, like Captain Mar-Vell, his son Hulkling and Mar-Vell’s half-Kree successor Carol Danvers.

6 Michael Korvac Is A Powerful Cosmic Cyborg From The Future Who Wants To Remake The Universe

Michael Korvac wields cosmic power in Marvel Comics

Reality has almost been erased and rewritten on more than one occasion by the powerful villain named Michael Korvac. The Avengers' greatest encounter with the deadly android from the future came during “The Korvac Saga.” Earth’s mightiest heroes worked with the original Guardians of the Galaxy members to save reality.

Korvac was transformed into a cyborg by alien invaders in the future as a punishment. However, this ultimately allowed him to hack into Galactus’ ship and steal his cosmic power. Korvac and his plans to rewrite reality were stopped. However, he displayed his power by killing most of the Avengers before bringing them back to life.

5 Norman Osborn Earned His Reputation As One Of Marvel’s Greatest Villains During His Dark Reign

Norman Osborn in his armor with Super-Adaptoid's powers

Some of the most evil things Norman Osborn has done were to Spider-Man as his arch-nemesis Green Goblin. However, he has become one of the Avengers’ greatest enemies as well. Osborn was able to gain a high position as the director of the government’s Thunderbolts. He then used a pivotal moment during the Skrull Secret Invasion to take power before the Dark Reign event.

Osborn formed his own Dark Avengers using villainous Thunderbolts in disguise as their heroic counterparts. He discredited the team and nearly brought them to an end in the Siege event before he was stopped. Osborn would later return with the abilities of the Super-Adaptoid and a new team of Dark Avengers. His attempt to regain power took multiple Avengers teams to stop.

4 Mephisto Is A Demonic Hell Lord Who Has Plagued The Avengers And The Marvel Universe For Eons

Mephisto in Marvel Comics

The demon known as Mephisto is the ruler of his own hellish realm that he uses to prey on humanity’s fear of the devil. Mephisto is known as a deal maker and has tried to corrupt more than one member of the Avengers over the years. While he doesn’t always engage in battles with the team, Mephisto is almost always operating behind the scenes.

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The Avengers have recently learned that the demonic Mephisto may have had his claws in the history of the Marvel universe for longer than they had imagined. Mephisto’s manipulations even affected the Avengers of 1, 000, 000 B.C., which further tied the villain to Earth’s mightiest heroes.

3 Ultron Was Created By An Avenger But He Ultimately Became One Of The Team’s Deadliest Enemies

The merged form of Ultron/Pym in Marvel Comics.

Founding Avenger Hank Pym/Ant-Man was a brilliant scientist who accidentally created the first artificial intelligence when he designed a robot known as Ultron. The robot began to evolve and recreate itself until it became Ultron-5. This was the first version to actively challenge the Avengers on its own.

Ultron would return many times over the years with new and improved bodies that almost tore down the Avengers. The robotic villain’s threat reached the stars in the Annihilation: Conquest event. Ultron was later forcibly bonded to its creator Hank Pym. Now known as Ultron/Pym, the villain has become a personal threat to the Avengers and the rest of humanity.

2 Thanos The Mad Titan Is A Deadly Villain Who Has Repeatedly Threatened Earth And The Universe

Infinity Gauntlet Cover with Thanos's face squashed agains the comic panel

One of the most powerful villains that the Avengers have ever encountered is the Mad Titan known as Thanos. The deadly villain was dedicated to impressing Marvel’s personification of Death. This drove him to find and use the Infinity Gauntlet to destroy half of the universe. The Avengers joined with other Marvel heroes to stop Thanos, though he succeeded in killing most of them.

Those deaths were undone when Thanos ultimately lost control of the Gauntlet, though that wasn’t the end of his threat. Thanos returned many times over the years to take on the Avengers in events like Infinity. The Mad Titan didn’t restrict himself to fighting the Avengers. He was also a threat to other cosmic heroes like Silver Surfer and the Guardians of the Galaxy.

1 Kang The Conqueror Is A Time-Traveling Villain From The Future With Advanced Weaponry

Kang the Conqueror with the Avengers

The time-traveling villain known as Kang the Conqueror was one of the first enemies the Avengers ever encountered. After his conquest of the future, Kang set his sights on the modern Heroic Age which brought him into conflict with the team. He utilized his incredibly advanced technology, weapons and futuristic armies against the Avengers numerous times over the years.

Kang has used other identities across time to attack the Avengers as well. His future self Immortus manipulated events in the team’s history. They also dealt with his past incarnations like Rama Tut and the Scarlet Centurion. One of the Avengers' biggest losses to the villain came during “The Kang Dynasty” storyline when he humiliated the team and briefly took over Earth.