Onaga the Dragon King originally formed the greatest army that Outworld had ever known; an army so powerful that it had never lost a battle. When Onaga was betrayed and killed by Shao Kahn, his army was entombed along with him after they ritualistically committed mass suicide since his death.
For millenia, this army of undead warriors would remain undiscovered in his tomb and await his second coming, until centuries later, the sorcerer Quan Chi discovered their location after his escape from the Netherrealm, and along with the help of another sorcerer Shang Tsung was able to revive it one by one. The young fighter Li Mei with the intention of freeing her home village, entered the Mortal Kombat tournament held by the Deadly Alliance, only to discover that the tournament itself was a setup; the Deadly Alliance was planning to transplant the winner's spirit as the last soul needed to completely revive the Dragon King's lost army.
When Li Mei's soul was almost transferred by magic powers of the two sorcerers into the mummified remains of one of the soldiers' cadavers against her will, it would seem that both her people are doomed to be slaves, and Li Mei herself would be reborn as a dead soldier, cursed to serve the Deadly Alliance forever. Until her teacher Master Bo' Rai Cho rescued her before that happened, yet that experience left some strange and strong supernatural influence on Li Mei, one that even draws her to her homeworld's long lost king. The Dragon King's army were completely destroyed in an ethereal energy blast caused by the thunder god Raiden's hara-kiri but their master Onaga, who had risen from beyond the grave, survived the explosion and continued forward to reclaiming Outworld, achieve his revenge and complete his plan of conquering the realms with the aid of a set of certain treasures with powers beyond comprehension.
After Onaga's return and eventual defeat, it was revealed that the army was only undefeatable due to his ability to constantly resurrect them during battle.
- The Dragon King's Army seem to be loosely based on the Terracotta Army.
- In the production gallery of Mortal Kombat: Deception, there exists a character called the Undead General, who is part of the Dragon King's Army, and is an obedient servant to Onaga himself.