Xerra

Xerra is a fourth planet of the Solar System which is replaced Mars, the homeworld of Terrians, Xenians, and humans. The name Xerra is actually a combination of "Xen" and "Terra".

Appearance
It is an Earth-like planet with rings. But on surface, there are mountains, valleys, canyons, and plains. There are also cities that they can be seen from space at night.