Eternians and etherians are humanoid species ressembling normal humans and genetically compatible with them. It has been hinted that they might be descendants from humans of the future.
They are the dominant lifeform on both Eternia and Etheria, sister planets orbiting a yellow sun whose exact spatial location remains unknown, although it has been hinted that it might be inside a space-time singularity, wether a junction of alternate universes or a pocket dimension caused by the presence, for a long time, of the Starseed at its core, a spark left over from the creation of the universe.
Some kind of wormhole exists linking Eternia's system to the Solar system and two space expedition have been known to fall through it.
Eternia is quite earthlike and has large bodies of water. It is separated into two very distinctive regions, the light and a dark hemisphere.
Eternians developped a technologically very advanced civilisation that has, for msot of it, regressed to a much more barbaristic state. Although some very advanced technology is still in use on the planet, it cohabits with magical science.
Apart from the dominant humanoid lifeform, the planet features an incredible variety of lifeforms, from monsters to sentient races.