Powers/Abilities: Illa is a sentient, "living moon"/planetoid/asteroid, and she possesses facial structures mimicking human eyes, nose, and mouth through which she apparently sees, (smells?), and speaks (she presumably speaks telepathically and mimics speech, but perhaps she can actually speak vocally. 

    The fact that she spoke English (as heard by Lunella) when she had never been to Earth supports more of a telepathic form of communication. 

    She is apparently unaware of anything outside of the field of view of her eyes.

    When she becomes angry, her surface may tremble, generating seismic tremors. 

    Drawing a picture on her surface may be ticklish for her.

    Portions of her surface appear to be more like a desert, with pink sandy ground and various chasms, buttes, rocks, and sparse vegetation. 

    Other portions are more like a forest or jungle, with trees and plants, as well as various forms of apparent fauna, including the "fleas" and some apparently reptilian creatures. 

    It is unrevealed whether the seeming plants and animals on her surface are extensions of her nature, of whether they are independent life that somehow developed there. 

    It is similarly unrevealed whether Illa has an atmosphere and/or whether it can support air-breathing organisms from life (see comments).

    The fact that Illa appeared to bounce off of Ego rather than burn up in his atmosphere and/or shatter against his surface may indicate she is not composed largely of ferrous metal like most asteroids. She can be seen to deform on impact but return to her previous spherical shape almost immediately thereafter. She may have been larger and had some of her previous mass burn off in Ego's atmosphere.

    While her consciousness exists within her entire mass, Illa can manipulate her surface to project forms to interact with others. 

    When Moon Girl arrived there as the first being to ever visit her, Illa spoke from her planetary mass, confusing Lunella. 

    Illa soon began projecting mounds with her face on it to speak and directly interact with those on her surface, after which she progressed to generating one or multiple humanoid forms of various sizes (some Lunella (3'9")-sized, some much larger than the 20' Devil Dinosaur. 

    Her forms varied in appearance with her mood, from more threatening and armored to more peaceful and vegetation-looking. 

    Presumably with time and effort she could perform some of the more complex tasks that Ego can perform (see his OHotMU profile). 

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History:
(Moon Girl and Devil Dinosaur#20 (fb) - BTS) - Apparently hurtling through space, the entity that would become the Living Moon crashed into Ego the Living Planet. Ego called her Illa, and she called him "Daddy" (she had struggled unsuccessfully to call him "father") before she began orbiting him in such fashion that her face was always away from him, and so she could not see him.

(Moon Girl and Devil Dinosaur#23 (fb) - BTS) - Telling himself that Illa's orbit was predetermined by forces of the cosmic consciousness, Ego decided that it was for the best as she needed to grow up to be independent, and that it was not his place to change the way things are.

(Moon Girl and Devil Dinosaur#22 (fb) - BTS) <Per Illa's understanding> - Illa was separated from Ego and waited "her whole life" ("...like a million <human> lifetimes") to find someone (see comments).

(Moon Girl and Devil Dinosaur#19 - BTS) - While Lunella Lafayette was searching for something in space via translation helmet communication array, she detected the voice of Illa, who asked for help. After Lunella boosted her signal, Illa asked where Lunella was, but she didn't know what Earth or even a planet was. Illa further noted that she had lost her father.

(Moon Girl and Devil Dinosaur#19 - BTS / Moon Girl and Devil Dinosaur#20 (fb) - BTS) - Lunella subsequently built a ship, the Moon Mobile, powered by the Kree Omni-Wave projector she had obtained, and she flew it into space, following Illa's signal to a moon a few light years from Earth

    Illa asked Lunella if she was the big red one or the other one, and Lunella had a hard time figuring out where Illa was until she realized Illa was the whole moon upon which they were standing. 

Illa noted with pleasure that she had been waiting her whole life for someone to find her.

(Moon Girl and Devil Dinosaur#20) - Noting that she didn't want to be alone anymore, Illa explained that she had never known her mother, after which she told of her encounter with Ego, whom she considered her father. 

    When Lunella drew a diagram in the dust of why Illa could not see her father, Illa had trouble appreciating the point because the process tickled her. 

    When Lunella noted a problem with the Moon Mobile, Illa told her she was too serious, and she insisted Lunella focus on her problem instead. Fearing the Omni-Wave projector, if not working properly, could send them to a parallel universe, Lunella asked to be left alone, which caused an irate Illa to tremble, causing seismic tremors. 

    When Lunella compared Illa to a dog with fleas, Illa confirmed that she had giant flea-like creatures living on her, but Devil and Lunella drove off the creatures.

    Needing some space from the erratic, Lunella flew herself and Devil away from Illa in the Moon Mobile, despite Illa's screams of protests, which overloaded the Moon Mobile's engine; as a result, the Moon Mobile delivered Lunella and Devil to "Earth-17885."

(Moon Girl and Devil Dinosaur#21) - When Lunella and Devil returned to Illa in the Moon Mobile, Illa told them that she was very mad at them, but that she would show them that she could forgive them...but that they could never leave her again. 

(Moon Girl and Devil Dinosaur#22) - Lunella eventually calmed Illa down, sympathizing with her feelings of loneliness. 

    While leading Illa to the appropriate location, Lunella noted her intent to bounce a signal off of an approaching comet -- which Illa believed to be her mother (despite Lunella considering this unlikely) -- and use it to project herself and Devil to Ego.

    Lunella manipulated Ego -- who considered Illa's position to be part of a cosmic plan -- into drawing Illa closer to him, bringing the two together. Illa was ecstatic.

(Moon Girl and Devil Dinosaur#23) - After Illa started to relate her life story to Ego, she told Lunella it was time for her to go while at the same time asking her father why he had not tried to alter their orbits so they could speak. 

    Ego told her of his previous reasons, noting that seeing her now had shown him that he could be wrong. 

    As Lunella and Devil departed in the Moon Mobile, Illa and Ego bade them farewell.