He did not make his "official" MK debut until the MK3 era. He was mentioned in writing before he was a character as well. The idea for Ermac came from the glitch in MK1 where Scorpion would appear red. He was an internet created persona that they called Ermac short for ERror MACro. Midway saw all the attention the fake character was getting so they decided to make him official. Now he's got his own backstory and he's totally awesomesauce.