Marvel Studios' 2021 film Eternals massively expanded the cosmic corner of the Marvel Cinematic Universe with the formal introduction of enormous beings known as Celestials. Celestials existed before the birth of the Infinity Stones and are responsible for the creation of many galaxies and the Eternals. While this is the first time they've been shown on this scale, this isn't the first time the MCU's heroes have encountered a Celestial being. In Guardians of the Galaxy Vol. 2, Ego the Living Planet claims that he is a Celestial as well. However, one theory believes he's something far more dangerous.

Since the arrival of Eternals, Ego's status as a Celestial has been brought into question. While there's no doubt that he's a powerful cosmic being, his abilities don't match that of the Celestials, though they are Celestial-esque. One theory from Redditor, willyolio, posits the idea that Ego is actually a parasitic being. The theory also describes Ego's purpose as something similar to another parasitic species in the Marvel Comics universe.

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Ego's Motivations May Parallel One of the Celestial's Great Foes

Various Celestial beings appearing in the sky

In the comics, the Horde acts as the opposition of the Celestials and appears on planets where the Deviant influence outmatches the Eternals. These creatures appear as insects and, by definition, act as symbiotic creatures to the Celestials. That being said, their threat could also reach the Celestials themselves as they feed on the same energy the beings emit. Ultimately, it becomes a race over who will obtain the most power first and claim the planet. While Ego doesn't appear as an insectoid being, his motivations, whether he knows it or not, could parallel the Horde.

In Eternals, the Celestial life cycle establishes that Eternals are placed on planets that contain the seed to a new Celestial. After centuries of feeding on the energy of a population, it emerges from the planet, destroying it. Comparatively, Ego's motivations to spread his influence follow a similar school of thought to the Celestials. In Guardians Vol. 2, Ego explains that he plants his own seeds on populated planets that offer identical energies to the ones Celestials look for. The theory adds that Ego even chooses a world that Celestials have seeded so he can feed on the benefits its energy provides.

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Ego Follows the Celestials as a Parasite

In essence, Ego isn't a Celestial. Instead, he's more like a parasite who follows the cosmic energy the Celestials leave behind. Like the Horde, whichever side gets more power first will be able to reap the benefits of the planet's energies. This also explains why Ego has never met other Celestials because they are actually avoiding him and his parasitic tendencies. Considering there are no others like Ego that have been shown, he could also be the last of his kind, explaining why he travels to these Celestial seeded planets instinctually, without knowing why.

Like the Celestials, Ego is an ancient being that has existed for centuries (or more). However, he may exist at a much lower level below the Celestials. However, it also begs the question of where that leaves Peter Quill and if he is still half parasite or cured of that side of his DNA. While this theory isn't confirmed, it paints a picture of how predators and prey exist in the MCU's cosmic universe. The theory also helps to introduce the terrifying scope that this universe is setting up in future adventures. Ultimately, Ego's potentially parasitic nature could be setting up the idea that there are even more significant and deadlier threats that may want to feed on smaller beings.

To see the power of true Celestials, Marvel's Eternals is streaming now on Disney+.