It's simple.
Quote Originally Posted by Lord Chainsaw
Is he a Lunarian?
Yes.
Why was he evil?
When they lost their homeworld, the Lunarians decided that they could populate the Blue Planet, but since it was already occupied by humans who had a quaint little civilization going for themselves, they decided the polite thing to do would be to sleep in the Lunar Subterrane until they had petered out. Zemus was just too stuck-up to wait millennia for the sake of what he deemed an inferior race, so he decided to speed up the process by forcibly wiping them out of existence.
How did Zemus come into contact with Golbez?
  • Golbeza was one of the only two earth people with any Lunarian blood in him. Zemus probably knew about them from tracking Kluya's progress on earth.
  • Unlike his brother, Golbeza also inherently had evil in his heart, making him a snap to manipulate.
Are he and Zeromus the same character? If not, then who is Zeromus?
Basically, Zemus hated the humans so much that he reached the point where there was just nothing to him but hate anymore. He lost sight of his original purpose (allowing his people to go down to earth, remember) and changed his objective from "destroy humans" to "destroy everything." In this transition, he became Zeromus. Another way of saying it is that Zeromus is the manifestation of the hatred that grew in Zemus's heart.