You probably didn’t even realize that the second character appearing in Guardians of the Galaxy Vol. 2‘s trailer was a character at all, but here he is: Ego the Living Planet, briefly spotted as Star-Lord looks at him from a ship. The Living Planet is, as you can guess, a planet, but he’s also Peter Quill‘s father in the movie, and he’ll appear in human form as well, portrayed by Kurt Russell. As far as we know, Ego had sent the Ravagers to retrieve his son before the events of the first movie, but after Peter gained quite a fame after holding an Infinity Gem and living to tell the experience, he’s finally able to find him on his own. Whether he’ll be an ally or a new enemy for his son and the other Guardians of the Galaxy is still unclear, but his comicbook counterpart isn’t exactly the nicest guy around. Let’s see together.
It was first believed that the (almost) unique being known as Ego the Living Planet was born naturally, a normal, inert planet, forcefully merged with a scientist studying it when the nearby sun went nova, gaining self-awareness this way. Even Ego himself, however, didn’t know it all: he was actually the result of an experiment from the Stranger, who created him and his “brother” Alter Ego, letting them evolve just to see if such creatures could actually survive in the universe, and which one of them was stronger. Ego completed his formation in the Black Galaxy, a dark nebula in which he was pretty much the sole living being. In order to survive, Ego started assimilating other nearby 
planets, and when the first spaceships started to explore the Black Galaxy, he consumed them too. Some of the destroyed ships belonged to Rigellians, an advanced race who wanted to expand in the nebula, but the only thing they achieved was to warn Ego of their presence, and the Living Planet started to long for a space outside the Black Galaxy. Ego’s new ambition of conquest put Rigellians in alarm, and the aliens decided to join forces with the Asgardian god Thor to repel the monstrous invader, in exchange of leaving Thor’s homeplanet Earth alone. Thor agreed, and accompanied Rigellian Recorder #211 to the Black Galaxy, where he engaged the massive Ego in battle: coming to sheer force, Thor was no match for the Living Planet’s powers, but eventually he found a way to defeat him, as he used his mystic hammer Mjolnir to unleash a powerful storm, that resulted in a global cataclysm. Stunned by the unexpected change in his atmosphere, Ego surrendered and, humiliated, retreated in the Black Galaxy, swearing not to leave it anymore. Not so many months passed, however, that Ego found himself forced to break his promise, as a deadly threat was approaching him: Galactus, the Devourer of Worlds, had chosen him as his next meal, and the Living Planet called for Thor’s help. The God of Thunder, believing Ego to be the lesser of two evils, decided to join forces with him, and borrowing some of Odin‘s powers, he came to Ego’s help.
Quite unexpectedly, Ego and Thor together managed to force one of the most powerful beings in the universe to retreat, and the Living Planet, out of gratitude, accepted the God of Thunder’s request: to host the Wanderers, the refugees from the first planet Galactus had ever eaten. Unfortunately, this peaceful state of things wasn’t meant to last: the Rigellian High Commissioner still wanted to study Ego, and he sent a Colonizer, Tana Nile, to collect a small sample of him to study it and to find out if it could be used for terraforming uninhabitable planets. 
This process went horribly wrong: not only the sample became sentient and, as Ego Prime, started wreaking havoc in nearby planets, but with a part of himself taken away from him, the original Ego went mad, and reversed to a primordial state driven essentially by survival instinct… and hunger. First, Ego consumed the Wanderers who lived on him, then he started destroying everything coming near him. Once again, it was Thor who realized the threat the Living Planet represented… and, quite ironically, the only one powerful enough to lend him a hand in dealing with Ego was Galactus. Ego was totally insane, and he didn’t even feel the slightest fear in seeing the Devourer of Worlds once again, on the opposite, he attacked him. Others intervened in the battle, and while Ego fought Thor, Hercules and Galactus’ herald Firelord, the Devourer of Worlds built an extremely powerful propeller, attaching it to Ego’s south pole. When activated, the device moved Ego away, allegedly bringing him away from any inhabited world or known route, so that he wouldn’t have been a menace for anyone. Things went exactly as planned for some years, during which Ego unwillingly traveled to the most remote corners of the universe… until he finally was able to use his psionic powers to gain control of the propeller. With some of his sanity back as well, Ego had just one thing in mind: exact his revenge on Galactus. Since he was last allied with Thor and Hercules, the Living Planet set a course on Earth, hoping to find the one responsible for his solitary exile: the universe would have once again felt his wrath.
Ego the Living Planet is an extremely intelligent creature, able to comprehend the universe better than most… but he’s also a megalomaniac with a cosmic-level superiority complex, that often leads him to plan conquers and wars starting from the simple assumption he’s better than any other life form. He’s also extremely powerful: virtually indestructible, being able to fully regenerate even from a few molecules, he also possesses vast psionic powers, resulting in telepathy and in highly destructive energy blasts that can destroy entire planets; he also controls his entire mass to a molecular level, being able to shape himself as he wants, changing the appearance and the atmosphere on his surface (usually using this to lure unaware explorers with promises of a flourishing world… and to eat them as they land), protruding organic tentacles and sensors, and even creating humanoid avatars to relate to smaller beings; he also possesses and controls special antibodies he uses to kill off the organisms resisting to absorption, and, using Galactus’ propeller, he can travel anywhere to light speed. One of the most powerful and unique creatures in the universe, Ego’s mind is quite fragile, and he often descends to madness: when a sentient planet is so emotional and irascible, nobody in his same galaxy can be safe…
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