Quan Chi's Fortress

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, and it is located in the Realm of Outworld.

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 himself astroprojects 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.

Death Trap
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.

Concept Art
In Mortal Kombat: Deadly Alliance, there was a concept art based on the exterior of Quan Chi's Fortress, but with another name for the villain's own citadel called "Shoal of Quan Chi" (or "Quan Chi's Shoal"): the evil sorcerer's lair is shown built on a shoal which is sandbar, (or just bar in context), or gravebar is a somewhat linear landform within or extending into a body of water like an island, typically composed of sand, silt or small pebbles. Shoals are characteristically long and narrow (linear) and develop where a stream or ocean current promotes deposition of granular material, resulting in localized shallowing of the water. Shoals like this one, often appears in a lake, in a river, or in a sea. On the Shoal lies a balcony-like road complete with a courtyard, riddled with huge stone heads resembling Quan Chi's face, built around the water and leads directly to the entrance of the fortress where the demon sorcerer Quan Chi resides.

TV appearance
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.

Trivia

 * Quan Chi's Throne should have made a reappearance 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. But for some reasons, it made it into the game's production and it ended up as the kontent picture in Deadly Alliance's own Krypt and Extras kontent gallery instead.
 * Strangley, when the player kicks its opponent into the pit of lasers, they turn from a spider-web pattern to a perfect square grid.