Lares

Lares is the only satellite of the planet Theia, the seventh largest of all planets within the Solar system.

Being quite different from most naturally formed satellites within the Solar system, this can be explained with its history; Lares was formed during the early Solar system, and after almost two and a half billion years of existence within the asteroid belt, it was knocked out of orbit, and plunged towards Theia. The planet caught the asteroid within its gravitational pull, and after hundreds of years of elliptical orbit, Lares' orbit around Theia stabilised.

Since this period, 2.5 billion years ago (Gya), Lares has maintained a steady relationship with Theia. Lares has been able to slow the planet's orbit period by way of tidal friction, and is one of the only reasons Theia has the abundance of land based life, as well as ocean going complex life it has been able to maintain.