IIRC the only energies are AIM, Mana, and Spirit Energy. 

Also, I personally cannot fathom aliens in a world where several universes have collided. I'd think if we had the science to give people superpowers, then we'd definitely have the science to conquer space (maybe even WITH the superpowers) and find things. It wouldn't quite be a matter of 'Zylar's Race is unknown', more like 'Zylar's Race is known, so is their name, population, society, etc', since I'd assume the planet made out of many dimensions would be able to find the alien planet first.

A custom demon or a hybrid, I can see, but not aliens, no. Or at least, not an alien in the traditional sense.