Throughout the Multiverse Saga, the MCU has explored beings far beyond the power of what had been seen before, and that should only expand as the franchise ventures beyond into Phase 5, 6 and 7.
After Odin's death freed her from thousands of years of imprisonment, Hela, the Goddess of Death, showed off her powerful Asgardian magic by crushing Mjolnir with one hand in Thor: Ragnarok, taking on the armies of Asgard with ease and overpowering the Revengers - a team of Thor, Loki, Valkyrie, and Hulk.
Going back to the days before Odin imprisoned her, Hela was clearly a force to be reckoned with, having been trusted by the All-Father to command Asgard's army and serve as his executioner. Together, they led a brutal conquest, bringing the Nine Realms under the control of Asgard.
Once the Crown of Surtur is united with the Eternal Flame, in his own words, his power grows as big as "a mountain." While, in his normal state, Surtur was fairly easily killed by Thor, once the Crown and Flame were united, the fire demon fulfilled the Ragnarok prophecy by destroying Asgard and Hela with it.
The only one who has been able to defeat an Eternal Flame-powered Surtur appears to be Odin, who he later became so fearful of that he waited until his disappearance to resume his efforts to bring about Ragnarok.
The MCU may have only shown off an older and weathered Odin, but in his prime, he was clearly among the most powerful gods to exist. The Odinforce combines magical and cosmic energy with Odin's own life force, allowing him to achieve impressive feats such as warping reality.
Prior to the events of the MCU, Odin defeated and took the Eternal Flame from Surtur, who, when he was reunited with that power source after Odin's death, was shown to be powerful enough to defeat Hela and destroy all of Asgard.
An inter-dimensional being and the ruler of the Dark Dimension, Dormammu was featured only briefly in Doctor Strange, but his power was instantly clear. His absolute control over the Dark Dimension and Dark Magic gives him a host of powers, including immortality and the ability to bestow that magic upon others.
Benedict Cumberatch's sorcerer even knew going into his confrontation that he wouldn't stand a chance in a battle with Dormammu. Instead, he had to trap him in an endless time loop where he killed him on repeat as he "came to bargain" for the fate of the world.
11.) The Watcher
The Watcher has only had one on-screen fight in the MCU, and that was against Ultron in What If...? Season 1. Although there's no denying that Uatu managed to hold his own fairly well against the Ultron Variant who was powered to insane levels with all six Infinity Stones, even surviving the destruction of a galaxy.
But usually, The Watcher sticks to observing the Multiverse from the Nexus of All Realities, having sworn an oath to never interfere.
10.) Strange Supreme
What If...? put unique spins on many of the MCU's heroes, including Doctor Strange, who had his powers dialed up in this alternate timeline. The Supreme Variant had his heart set on altering an absolute point in time to save Christine Palmer and as such dedicated his magical career to becoming more powerful.
He did so by absorbing gradually more powerful creatures, only adding to his power, eventually allowing him to hold together a small patch of his world with his magic after that universe collapsed. Strange Supreme was later integral to leading The Watcher's Guardians of the Multiverse against Infinity Ultron.
And even before that power boost, Marvel Studios themselves declared the familiar Doctor Strange as one of the MCU's two strongest heroes.
Next up comes Ego, the father to Chris Pratt's Star-Lord and a Celestial who is literally a living planet who can also take on a human form. Clearly, Kurt Russell's villain is insanely powerful, given his powers of matter and energy manipulation, strength, durability, and immortality.
The bottom line is that his god-like abilities allow him to truly do anything his mind could wish, all while being an immortal genius. The Guardians did eventually manage to defeat him by planting a bomb on his more fragile core that the planet and his humanoid body were designed to guard.
As one of the few Celestials featured in the MCU, Arishem the Judge must be considered among the most powerful beings. After all, on top of creating the Eternals and Deviants, he was responsible for creating the universe with stars, planets, and the first sun, planting seeds for more Celestials along the way.
Arishem has almost no regard for life in the universe, being fully dedicated to the role of the Celestials in the universe. After Eternals, Arishem will now be judging the people of Earth after his own superhero creations caused the death of Tiamut - the Celestial who was supposed to emerge from the planet.
With how Thanos was able to take on all the Avengers using the Infinity Gauntlet, go toe-to-toe with the Hulk without taking advantage of the stones, and wipe out half of all life in the universe, surviving the damaging effects of the stones, it is easy to see why he belongs so high on this list.
The Mad Titan demonstrated himself to be truly formidable even without the stones, only becoming more of a threat with them. Granted, when weakened by the stones he went down without much of a fight, but the prime Thanos to the full might of dozens of heroes and a major sacrifice to beat.
6.) Scarlet Witch
Wanda Maximoff was always one of the most powerful characters in the MCU, as was shown when she almost managed to single-handedly take down Thanos in Endgame until his ships rained fire. She even managed to fend off Thanos while simultaneously destroying Vision's Mind Stone in Infinity War.
Having since gotten access to the powers of the Darkhold in WandaVision, the former Avenger has gotten far more powerful in her new Scarlet Witch form. After all, she did take on the Illuminati and the entirety of Kamar-Taj herself in Doctor Strange in the Multiverse of Madness.
5.) Infinity Ultron
What If...? culminated with a battle between the Guardians of the Multiverse and a Variant of Ultron who managed to transfer his consciousness into Vision's body, use the Mind Stone to kill Thanos, and take control of all six Infinity Stones, making him a formidable foe, to say the least.
The Infinity Ultron was so powerful the Watcher had to break his vow not to interfere with the timeline. Wielding the Infinity Stones, Ultron was able to destroy galaxies and casually tear through planets, he was only defeated by a virus that took over his programming.
4.) Kang the Conqueror
Kang the Conqueror was declared by Disney themselves as "the MCU's most powerful villain to date," noting his trustworthiness and ability to "rewrite existence and shatter timelines." He even revealed that he has killed countless Avengers before, seemingly including the God of Thunder himself, Thor.
Jonathan Majors' Kang may appear to have been taken down by Earth's heroes in Ant-Man and The Wasp: Quantumania as he was expelled into the Multiversal Power Core, but he will almost certainly be back, more powerful than ever.
Alioth was introduced in the climactic episodes of Loki as the shark in the shark tank that is the Void. But long before the trans-temporal entity was consuming those who had been pruned by the TVA and abandoned at the end of time, Alioth was discovered by He Who Remains.
The 31st-century scientist Nathaniel Richards discovered Alioth during the Multiversal War and used them to put an end to the conflict by wiping out whole timelines and taking down countless Kang Variants in the process.
2.) He Who Remains
Alioth may be the being that served as the guardian of the Void and was used to win the first Multiversal War, but that has to place the one who was able to harness its power one step above - that being the Kang Variant, He Who Remains.
After eliminating countless timelines and Kang Variants, He Who Remains was able to script the whole Infinity Saga and condense reality to just one Sacred Timeline that he created the TVA to manage. That much control and mastery over the timeline undoubtedly make him one of the most powerful geniuses out there.
But Thor: Love and Thunder introduced the MCU's true most powerful character yet, Eternity. The ancient being exists in its own realm accessed only through the Gates of Eternity, with the promise to grant any one wish of the first person to reach it, who proved to be Gorr the God Butcher.
Despite initially planning to use this wish to obliterate all the Gods in existence - which in itself would be an insane feat for Eternity to deliver on - Gorr ultimately uses it to resurrect his deceased daughter Love, which again marks an impressive showcase of power.
Eternity may be the most powerful being in the MCU's history for now, but there will undoubtedly be more to come throughout the rest of the Multiverse Saga and beyond that will top them. For one, Avengers: Secret Wars will likely bring the debut of the all-powerful Beyonder, a nearly unparalleled cosmic entity.