Reptile's race.

They were originally from Earth, but the war between Raiden and Shinnok practically wiped out their civilization. What was left of them moved to the realm of Zaterra.

Explained in Khameleon's Trilogy ending:
"They evolved millions of years ago on Earth into intelligent creatures but fled the realm when it was destroyed in a battle between the gods. They repopulated a new realm known as Zaterra...."

It was reptiles race. The only way Raiden would not have to wipe out a whole population was to give up earthrealm to Shinnok.

But he chose to fight shinnok instead, causing the elimination of most of Reptiles race.

I believe if Reptiles race were to ever be populated again, it would start with reptile and khamelion..

^ Or Chamelon, that would make more sense, just saying.

XD84's got the answer covered, so the thread can be closed.