A sorcerer from the Netherrealm, Quan Chi is quite easily the most treacherous
character in all the games. While originally supposed to serve the Elder God Shinnok, Quan Chi's true allegiance is only to himself, and he will make and break deals with anyone if it furthers his goals. Quan Chi, contrary to most characters in the series, does not actually belong to either a mortal race or the myriad gods: he used to be an oni, a demonic torturer from hell, who eventually took a humanoid form.
Quan Chi has had a behind-the-scenes presence through a myriad of major events in the series' history. Serving Shinnok, he directly caused the deaths of both Scorpion (and his clan and family...) and the original Sub-Zero, was the one who revived Sindel in order to facilitate Shao Kahn's invasion of Earthrealm, released Shinnok from his imprisonment in the Netherrealm, and brought about Liu Kang's death during the events of Deadly Alliance
. He has also betrayed every single ally he ever had at one point or another.
During the events of both Mythologies: Sub-Zero
and Mortal Kombat 4
, Quan Chi was working to release his master, the banished Elder God Shinnok, from his imprisonment in the Netherrealm. To this end, he also worked with Shao Kahn (bringing back Sindel for him, as previously mentioned). After Shinnok's defeat, however, Quan Chi eventually discovered the tomb of Onaga The Dragon King, which contained within his undead army, which slept in suspended animation. Wanting to control the army to conquer both Outworld and Earthrealm, Quan Chi allied himself with Shang Tsung, eventually bringing down Liu Kang together during the events of Deadly Alliance
. Of course, after being victorious over Earthrealm's warriors at the end of Deadly Alliance
, Quan Chi turns on Shang Tsung (with Shang Tsung doing the same, of course). They are both attacked by Onaga the Dragon King, however, and both Quan Chi and Raiden are supposedly destroyed during the events of Deception
. Quan Chi did survive the events of Deception
, but eventually dies along with... well, everybody else, during the events of Armageddon
Quan Chi has an important role in the events of Mortal Kombat 9
: all the aforementioned events which happen during the course of the first three games also happen during this one. It starts with the fact that he slaughters Scorpion's family to convince him to kill the original
Sub-Zero, not the younger one, and it only goes downhill from there.