Making his debut in Mortal Kombat 3, Cyrax was one of the four cybernetic ninjas created by the Lin Kuei, in an effort to convert all members into unfeeling, cold-hearted, cybernetic assassins to improve their performance. He was assigned to hunt down the renegade, former Lin Kuei member Sub-Zero as designated unit LK-4D4. Of the four cyborgs, he has become the second to recover his humanity. This is due to the efforts made by Sonya Blade and Jax Briggs. He has currently allied with them as a token of his appreciation. In the alternate timeline, however, he was automated and dutifully serves the Lin Kuei. Cyber Sub-Zero reclaims his humanity instead of Cyrax.
He and his robotic counter-parts, Sektor and Smoke, began as palette-swapped characters to work around technical limitations to increase the number of playable characters. Since their appearances in the MK3 series, each character's appearance has evolved independently. Of late, they have only appeared in Mortal Kombat: Armageddon together. While Sektor and Cyrax were playable in Mortal Kombat Gold, only Cyrax was playable in Mortal Kombat: Deadly Alliance, while Sektor appeared in Mortal Kombat: Tournament Edition. Smoke was playable as part of a tag-team with Noob Saibot in Mortal Kombat: Deception. However, they all have returned for Mortal Kombat: Armageddon as individual characters.