Origin

Before the First Cosmos, there was nothing, a state of nonexistence designated the Zeroth Cosmos. The First Cosmos was born in causal loop.^[11] Long after the First Cosmos' shattering into the Multiverse, after many multiversal cycles, the Seventh Cosmos was destroyed, and it was reborn as the Eighth Cosmos by a man named Reed Richards.^[12] Inadvertently, Richards created the Grail, a flaw that materialized as a grail and could birth a new cosmos, destroying the current one.^[13] After the Grail had been activated by Myrddin, the Avengers and Twilight Court opened a portal to the Zeroth Cosmos, where and when there was no cosmos to destroy. A third party, the Ashen Combine, stole the Grail and fled through the portal without realizing its destination, sparing the Eighth Cosmos and birthing the First Cosmos.^[11]

Celestial War

Embodied by the First Firmament, the First Cosmos was the very first universe to ever exist. During the Celestial War, the Celestials detonated their unimaginable weapons against the Aspirants, shattering the First Firmament into pieces. The hundreds of new universes born from those pieces coalesced into the first Multiverse and its personification.^[4]

In accordance to the Celestials' desire, all subsequent universes had a lifespan. The Multiverse itself went through renewal cycles, in which all of creation ended and began again. The current Multiverse was the Seventh Cosmos, but it was later destroyed and reborn as the Eighth Cosmos.^[4]

Shortly after the creation of Earth in the Seventh Cosmos, the ultimate creator of all of existence, the One Above All, used the fragments of the First Firmament to construct indestructible chains to imprison the Mother of Horrors in the Requiem Plain, after His other half, the One Below All utterly destroyed her and her wicked spawn.^[14] Some of these chains, which would come to be known as the Chains of Uthl, would fall in the hands of the Mother of Horros' first child, Eldest, and use them to restrain the Hulk.^[15]

Infinity Wars

According to an alternate Loki with all the Infinity Stones, "the original universe" can be accessed by breaching the bottom of the Quarry of Creation, but all the stones are needed to do so.^[5] The prime Loki, after collecting all the stones, entered the original universe and found out that it is full of Infinity Stones and Celestials.^[10] He asked the Celestials to show him his future^[6] and was shown his past self entering the House of Ideas.^[16]

Avengers Assemble

Mephisto, the Council of Red, and Doom Supreme all attacked the God Quarry to access the First Firmament.^[8][17] To prepare, they destablized the Multiverse as much as possible to weaken the boundary.^[18] After it was breached, Doom Supreme attempted to harness the First Firmament's power to remake the Multiverse but was overwhelmed. Mephisto planned it to end the Multiverse but was thwarted by the Avengers. They could not plug the hole from the God Quarry, so Robbie Reyes entered the First Firmament to seal it from the other side. He remained there, waiting for the chance to return.^[7]

In the remnant of the First Firmament below the Quarry of Creation, there exists Celestials and Infinity Stones. The Celestials have a mysterious, black mirror or window. When Loki breached the Quarry, he looked through, believing it would show him the future.^[10] Instead, it showed his past self and it connected to another mirror on the Outside, right by the door to the House of Ideas.^[16]

• Aspirants
• Celestials
• Exterminators^[3] (formerly)
• Cal-Horra^[19] (formerly)
• Nemesis^[20] (formerly)

• Two other different accounts as to how the First Cosmos was split into the Multiverse were presented throughout the years:
  • Nemesis, the only living thing that existed within any and all realities, chose to put an end to itself because of its loneliness. From its ashes rose the Multiverse as well as the six Infinity Gems, the reincarnated form of the being's might.^[21]
  • The Celestials, wanting symmetry, created the Exterminators to be the death to the life they made from the darkness. When their creations turned against them, the Celestials split the universe into the Multiverse and sealed the Exterminators into one of those universes.^[3]
• In Avengers Forever (Vol. 2) #15 and Avengers Assemble Omega #1, the First Firmament is erroneously described as a Multiverse.
• The First Cosmos did not go through cycles and did not "age." If not for the Celestials, it would not have ended.^[4]

• The Celestials that Loki encounters are not identified in Infinity Wars #5–6; however, a flashback from Wolverine: Infinity Watch #5 reveals that two of them are Ziran the Tester and Nezarr the Calculator.
  • Defenders: Beyond #5 labels these Celestials as the "First Celestials."