Theia

Theia is the name of a hypothetical Mars-sized object that led to the creation of the Moon.

In real life
In real life, Theia is the main focus of the Theia hypothesis for the formation of the Moon. The hypothesis's basis is that early in the formation of the Earth, gravity shenanigans sent this object on a collision course towards Earth. When the two collided, Earth was presumably shot onto it's current angle (23.5 degrees) and a ring system formed. The rocks collided with each other leading to an object being formed, that being the Moon.

Appearance
Theia seems to be related to Earth in terms of body structure, likely suggesting Theia is female, too. Theia likely doesn't have anything else, as Theia was either killed or is masquerading as someone else.

Personality
Theia's personality varies, but it's likely Theia was attempting to attack Earth early in the formation of Soltown, but died in the process, leading to the Moon.