Introduced in Mortal Kombat: Deadly Alliance, Quan Chi's Fortress is the interior of the wicked necromancer Quan Chi's own home and hidden citadel. It is located in the Realm of Outworld in the first timeline and in the Netherrealm in the second timeline.
It features the fighting arena on the right and Quan Chi’s inner sanctum in the "centerfield". The glowing egg in the background is the inner sanctum, a chamber protected by magical runes that covers it, where Quan Chi leaves his body, periodically recharging his power as well as astroprojecting his consciousness to other planes of existence. The center ring rests above a network of lasers. The lasers make a spider web pattern which is fitting for this evil sorcerer.
In Mortal Kombat X, it has a more library-like appearance with a display containing the armor of Shao Kahn and a separate, interactive stand for his Wrath Hammer. On the opposite side of the room is a stairway leading up and a view to the Netherrealm outside. In the centre of the room is a pit of blood where an incomplete flesh construct periodically rises. Throughout the room are skull-patterned pillars reminiscent of the Fire Well stage.
This arena featured a death trap when it returned in Mortal Kombat: Deception, in which it had laser fields below. The lasers make up of a spider web pattern, and when the opponent is knocked off the platform, they free fall until they're sliced to pieces by the lasers.
In Mortal Kombat X, Quan Chi's Fortress features four arena interactions. From farthest left to right, they are:
- A spine shaped lamp post that can be used to strike the opponent with for a cinematic attack. The attack can be used to strike the opponent's legs if a directional input is used.
- A small torch in the shape of an orb that can be thrown at the opponent as a projectile that can cause them to stumble.
- Once thrown, the chest the lamp was set upon can now be used to for kombatants to jump across the area.
- A jar containing a fetal demon. This interactable has two options for use;
- All characters are given the option to throw the jar as a projectile to deal damage.
- All characters are given the option to slide into the jar to cause it to explode, which will launch the opponent into the air for a juggle effect.
- Shao Kahn's Wrath Hammer that can be used to strike the opponent with, knocking them to the ground
- Using the Shao Kahn's Wrath Hammer interactable as the final hit of the match while pressing a button input will result in the Hammer destroying the opponent's upper body on impact.
The demon sorcerer Quan Chi has another, yet hidden lair called Quan Chi's Palace in Outworld, secretly built and away from prying eyes, and it is first featured in the 9th episode "Quan Chi" of the TV series Mortal Kombat: Conquest and appeared throughout the entire series. It is somewhat a grand yet, sinister-looking, dome-like palace with a yin-yang emblem above its front doors, built inside a mountainside with 5 claw-like rocky pillars over it. Inside his sanctuary is where Quan Chi resides and his beautiful assassins Siann, Sora and Mika report back to him of their findings, successes and even failures. It is where they're usually mistreated by him, even being called miserable sluts when Quan Chi himself becomes displeased and disgusted.
- Quan Chi's Throne was originally set to make an appearance at Quan Chi's Fortress in Mortal Kombat: Deadly Alliance as the background furniture in front of his inner sanctum for the sorcerer's own citadel. For unknown reasons, it never made to the game's final version and ended up as a kontent picture in Deadly Alliance's Krypt and extras kontent gallery instead. It was not until Mortal Kombat X that it would make an alternative appearance as a seemingly-obsidian leather throne within the Fortress in the game's Story Mode.
- Strangely, when the player kicks its opponent into the pit of lasers in Deception, they change from a spider-web pattern to a perfect square grid.
- In Mortal Kombat X, Kotal Kahn's Macuahuitl, Scorpion's Ninja Sword, Quan Chi's sword as well as Kenshi's Possessed Demon Sickle can be seen in the background.
- Quan Chi's Fortress appears in the animated movie Mortal Kombat Legends: Scorpion's Revenge, where Scorpion fights Quan Chi.