Lucifer

Lucifer is the former ruler of the Netherrealm.

His name is a reference to the Devil of Christian theology and implies that the two are one in the same. If so, that would seem to make a definitive identification of the Netherrealm as "Earth's Hell".

No explanation has ever been given as to Lucifer's origins or how he became the ruler of the Netherrealm. However, he held this position at the time of Shinnok's defeat by Raiden and the Elder Gods and his subsequent banishment to the Netherrealm. Lucifer was responsible for the constant torture Shinnok suffered for millennia. Shinnok remained at his mercy until meeting and allying himself with the sorcerer Quan Chi. Together they were able to overthrow Lucifer, and Shinnok was installed as the Netherrealm's new ruler.

As his fate after Shinnok's usurpation is not specified, Lucifer's current status is unknown.