The Tomb as its name simply and ironically implies, is an ancient tomb-like tower located in Outworld that has became a place of kombat during the fallen Elder God Shinnok's reign of terror upon the realms and his never-ending vendetta against the Elder Gods in Mortal Kombat 4 and Mortal Kombat Gold.
The Tomb is a monastic, yet evil tower found in the realm of Outworld and its interior is built like catacombs. At the top of the Tomb's upper lever lies an arena-like shrine with a skull-like window feature in the middle of the room. A body of a fallen warrior is found lying atop an altar at the rear of the room while there are coffins with dead people buried inside on each side of the chamber within the Tomb.
However, the people buried here in this forgotton and sinister crypt-like temple happened to be members of the Brotherhood of Shadows, Shinnok's faithful worshippers who kill and destroy in his name.