Cosmic beings capable of creating or manipulating entire universes, who desire worship and are almost immune to attack, litter the Marvel Universe. It would seem whenever Marvel needs a universe-threatening menace they create a new one to add to their already existing pantheon.
These beings in order of power (as defined by Marvel):
One-Above-All
The most powerful of Marvel's supreme beings uses an appellation that has been applied to two entities. To distinguish them, the Supreme Being is dubbed the One-Above-All (with hyphens).
The One-Above-All (not to be confused with the Celestial with the name, The One Above All) claims to be the first and most powerful entity in the Marvel Omniverse.
The One-Above-All has another potential identity as The Fulcrum. The Fulcrum is also the Bartender who runs The Vestibule, a swinging bar where Eternals go before they either return to a newly regenerated body or head off to Lacuna (The Afterlife). Said to be "all-powerful" and "all-knowing", the Fulcrum is likely an aspect, manifestation, or alternate name of the One-Above-All.
He is omnipotent, omniscient, and omnipresent. He is the most powerful being in the Marvel Omniverse. His power is unlimited, incalculable and immeasurable.
The Living Tribunal: is considered to be the right hand to the One-Above-All, he is the cosmic arbiter of what is right in the Multiverse and is capable of dispensing justice as he sees fit.
- Undoubtedly the most mysterious character within the Marvel Omniverse. The One-Above-All has only appeared and been mentioned a few times. He is not to be confused with One Above All, the leader of the Celestials, or any religious figures. The One-Above-All was first mentioned by the Living Tribunal when Doctor Strange first encountered the entity. The One Above All is often unofficially cited as Marvel's creator. ~ComicVine
The Beyonder
As much as it pains me to do this I must include the entry of The Beyonder. Despite his hokey and completely contrived origin for the Secret Wars Sagas, he has by virtue of materials written about him after the Secret Wars, the second most powerful being in the Marvel Multiverse. I will keep it brief:
- The Beyonder was originally from an infinite realm beyond the Marvel Multiverse, called the Beyond-realm, and was the sum of everything outside the multiverse (our multiverse was a drop in the sea compared to the Beyond-realm). It became self aware and formed a being of immeasurable power. (He was originally described as millions of times more powerful than the entire multiverse.) ~Comicvine
- The Beyonder was, at one point in his history more powerful than all the conceptual beings in the Marvel Universe and even manages to kill Death itself.
This picture shows The One Above All (Celestial), The Stranger, The Living Tribunal, Master Order and Lord Chaos, Eternity, The Watcher (lower left) The In-Betweener (in black and white) The Beyonder (in the orange jumpsuit), Mephisto (in red) and Death.
The Beyonder was vain, arrogant, annoying, petty and capricious. But there was no denying his powers. At his peak he would have certainly been considered omnipotent, his raw power having the ability to do anything he wanted, but he lacked a clear understanding of the Universe so he is not omniscient (unless he wanted to be) and not omnipresent (unless he thought about it).
One final note: The Beyonder has been retconned MANY TIMES. His origins are no longer clear to anyone and his recent appearances claimed he might be a mutant or he might not. Don't think too hard on it. If you're lucky, you'll never see him again.
One other note: The Molecule Man who depending on when you ask, derived his powers from the Beyonder or the Beyonderverse as well, so he would also be in the same class as the Beyonder, capable of creating entire universes if he so desired. He's currently dead, but since he has resurrected himself in the past, his death is "relative" and likely not permanent.
Galactus, The Devourer of Worlds
Galactus, The Devourer As Galan, Galactus is the only survivor of the universe that existed before the Big Bang. He was actually born billions of years ago on the planet Taa.
Galactus was the sole survivor of the previous universe and whose presence and absorption of worlds was learned to hold back the destructive capacity of the fourth conceptual being named Abraxas, the embodiment of Universal Destruction.
The Eldest
The Eldest: The four oldest beings/forces in the Marvel Universe. They are the First and arguably the most potent forces to exist in the MU. They view each other as siblings.
Death or Mistress Death was the first power to exist after Galactus. Death is one of the most powerful beings in the Marvel Universe. She often appears as a skeletal figure in a purple cloak but can appear as whatever she wishes. Mysterious, she almost never speaks and rarely makes personal appearances. For a time, the mad Titan Thanos, sought to kill half the Universe, using the Infinity Gauntlet to win her favor.
Eternity and Infinity: Cosmic entities capable of shaping reality as they see fit, since it comprises their very being. Almost nothing is beyond the capacities of these two beings, but they rarely interfere in the day to day operations of the Universe-at-large, recruiting agents such as Doctor Strange to do what must be done, since if they do it, they have the potential to disrupt wide swaths of their own internal reality. The equivalent of using a nuke to kill an insect.
Oblivion: is the personification of entropy which is the collapse or death of the universe. He is the male counterpart of Mistress Death. He has created many avatars or agents including Malestrom, Mirage and Deathurge. He is devoid of matter and energy and only seeks to return the Universe to the nothing that it was spawned from. Not invited to many parties.
Abraxas: The embodiment of universal destruction, a being whose powers rival the other three and is capable of envisioning and completing the destruction of an entire universe using the Ultimate Nullifier. This is an incredible feat because he has to be able to envision the universe in its entirety before using the device. He is also able to resist being destroyed after using the device.
While these beings can take on humanoid forms, they are NOT even remotely human. Their power is so great, even seeing them in their raw form can drive mortal lifeforms crazy.
The Cosmic Beings
Cosmic Beings, also known as Abstract or Conceptual Entities: These are the beings which form the underpinnings of the Universe and help to bring order out of the cosmic chaos.
The Phoenix Force as the Embodiment of Life is considered to be Death's antithesis. Her powers of creation and destruction are without peer and she (while wearing the form of Rachel Grey) fought Galactus to a standstill.
Master Order and Lord Chaos: These two are the living embodiment of Order and Chaos in the Universe. Lord Chaos and Master Order always exist together in the cosmos.
Lord Chaos asks Master Order questions and Master Order attempts to answer them to Lord Chaos' satisfaction.
Their agent in dealing with mortal beings, who helps maintain the Universal Balance between Order and Chaos is the In-Betweener, a being in between all conflicting concepts and thus immune to almost any form of harm by most mortal beings in the Universe.
These two are not above recruiting lesser beings to restore Order (or Chaos) to the universe if necessary.
There are others entities who embody other cosmic concepts such as Master Hate and Mistress Love. These are not lifeforms, they are conceptual beings who play some part in the maintenance of the functions of the Universe. In the case of Shuma-Gorath and the Many Angled Ones, they are part of some underlying fabric of the Universe formed after its creation.
There are also at least two artifacts capable of similar universe-altering transformations. Both were believed to be artifacts of the One-Above-All.
The Heart of the Universe: The Heart of the Universe is an object of infinite proportions. It's possession makes the user the supreme being of the Marvel Universe capable of shaping reality as they saw fit. The Heart of the Universe was presumably created by Marvel’s Supreme Being to correct an imbalance in the fundamental architecture of the Marvel Universe.
The Infinity Gems: The Infinity Gems are six precious stones of cosmic origin that give the possessor mastery over a certain power. Collecting and using all six gems will give the wielder complete control over the universe. Only the Living Tribunal, judge of the Multiverse, is immune to the wishes of the wielder of the Infinity Gems.