Sai Anand, Socrates Carvopolis, Entropy, Ivan, Adam Qadmon, Shakti
Inapplicable; the general populace of Earth is unaware of Eternity's existence
Place of Birth
Strange Tales #138 (1965)
It is theorized that Eternity (along with Death, Oblivion, and Infinity) came into existence at the precise instant of the big bang. The current universe was birthed from the ashes of the previous universe, the native universe of Galan (Galactus' previous mortal self). As the embodiment of the universe, Eternity is the supreme being of this reality. Eternity is everything and he controls everything in the prime material plane. However since it is not in Eternity's nature to act as a being, he generally does not take direct action in steering the destiny of the universe. Rather, Eternity just meditates on the pure idea of continuity. That is to say Eternity merely sets things into motion that cause a sequence of events that likely ensures the continued existence of the universe that he embodies.
Only in the direst of circumstances does Eternity directly intervene, as when he confronted Thanos when the former was in possession of the Infinity Gaunlet -- a collection of six Infinity Gems that when used in unison allowed Thanos complete mastery over the Mind, Space, Time, Reality, Power, and the Soul.
Eternity does not usually take sides in the eternal struggle between good and evil. Eternity is only concerned with the continued existence of all that is (an arguably selfish motivation which is only incidentally benevolent). As a passive being, his power has time and again been used by others for evil ends.
Such was the case when the powerful extra-dimensional being known as Nightmare attempted to seize Eternity from the inside, using all sleeping sentient beings (usually one-third of the total lifeforms in the universe and therefore a powerful minority of Eternity) to drive Eternity to sleep, thereby putting Eternity under Nightmare's control. In this state, Eternity was induced to dream planet Earth's obliteration. Doctor Strange, who possessed the Gift of Extended Life, did not die, and journeyed to Nightmare's realm, there to free Eternity and persuade him to recreate Earth. As Eternity is the sum total of all living forces, destruction of Eternity may eradicate the universe, and with it all other quasi-physical entities. Death and Eternity exist as partners, not competitors, and Death has never shown and "rivalry" (at least until the Infinity Gauntlet, one such event that comes to mind) against it's "sibling". Eternity, for its part, has rarely shown any interest in the pieces that make it up, though if given sufficient threat (on the level of the Beyonder, for example) would willingly sacrifice part of its infinite existence (and the planets, stars, and lifeforms that make up that existence) to foil such a foe.Also, there is the time when Eternity appeared to testify on the behalf of Mister Fantastic, at the urging of Galactus, when Reed was abducted by a group of survivors of Galactus' feedings. Eternity testified that Reed acted out of compassion, and not out of malice, in reviving Galactus. Saying that Galactus does indeed play a part in the universe, the accusers were satisfied, and Reed was released.