Forgotten Sepulcher

The Forgotten Sepulcher is a fifth level biome.

According to the loading screen quotes, it was once a tomb for important officials and nobles but was abandoned after the Malaise epidemic. The burial rites included killing the delegations of the entombed dignitaries and using their bones to decorate the walls. The only one left behind not infected by the malaise is the crypt keeper, a mysterious figure who keeps the lights that repel the darkness clean.

Access and exit
The is required to access the Forgotten Sepulcher from the Stilt Village. There are also entrances from the Slumbering Sanctuary and the Graveyard.

There are two exits out of the Forgotten Sepulcher. The main exit leads to the Clock Room, where the Time Keeper awaits.

After beating the Giant once and with at least 2 BSC active, a door leading to the Guardian's Haven can be accessed, where the Giant awaits. This door always spawns near the exit to the Clock Room.

The Darkness
The Darkness is a mechanic found only in the Forgotten Sepulcher (unless the Custom Mode gameplay modifier Follow the Light is enabled). The level appears dark except for permanent and temporary light sources, which illuminate small areas around them. The temporary sources are activated when the player touches them and burn out after a while.

If the player has been away from the light for 12 seconds, the Darkness begins to eat away at their health. The damage gradually increases from 0.1 to 6 per tick, with ticks every 0.3 seconds. Going near a light stops the damage and resets the 12-second timer and damage per tick. Killing an enemy reduces the Darkness by 11%.

Darkness damage does not trigger death by curse, and the mutation Disengagement does not protect from it.

Explorer's Rune
A room with two elite Dark Trackers can be found at the end of the biome. Defeating those elites gives you two Crypt keys, which are required to proceed to the room beyond two elite room, which contains the. Those rooms stop appearing after obtaining the rune.

Scrolls
The Forgotten Sepulcher contains 3 Power scrolls with a fourth located in a cursed chest and 2 Dual-Stat scrolls, which cannot spawn in areas requiring the Teleport, Ram or Spider runes. On (4+ BSC), there is a bonus Power scroll. When 3 Boss Stem Cells are active, this biome has 2 guaranteed Scroll Fragments, and when 4/5 Boss Stem Cells are active, this biome has 3 guaranteed Scroll Fragments. These can spawn in areas requiring the Teleportation Rune, but not the Spider Rune.

Enemy tier and gear level scaling
In the table below, you will find the gear level and enemy tier of the Forgotten Sepulcher based on difficulty.

Boss Stem Cells rewards

 * 2 BSC: Exit to Cavern
 * 2 BSC: Chained item altar
 * 3 BSC: Treasure Chest

Chests and loot

 * 1 Treasure Chest behind awakened doors.
 * 2 separate cell vats containing 6 cells behind awakened doors.
 * Elite room.

Shops

 * Skill or Weapons shop

Enemy blueprints
The blueprints for the Spiked Shield and Death Orb can only be found in this biome and in the Morass of the Banished (requires the Bad Seed DLC) and are looted from Cleavers.

Enemies
Corpulent Zombies can only be found in this biome. In addition, Cleavers could also be considered iconic of the Forgotten Sepulcher, as it could only be found here in older versions of the game. Other enemies that can be found here include Shockers, Kamikaze, and Inquisitors, as well as Knife Throwers, Weirded Warriors, and Failed Experiments on higher difficulties.

The table below lists which enemies are present in the Forgotten Sepulcher on each difficulty level and which blueprints each may drop. When applicable, the minimum difficulty level for blueprint acquisition is specified.

Alchemist grimoires
Main Article: The Alchemist

The Alchemist was researching the Malaise in the Forgotten Sepulcher, but the bodies kept waking up. In addition, the Darkness was making his work difficult. This prompted him to leave the area.

Other lore rooms
Nathan Drake, the protagonist of the Uncharted series, is found dead in a pit. He was looting sarcophagi but never managed to get back up because his rope was too short.

Trivia

 * Before the v1.1, the Pimp My Run Update, the 26 minutes timed door used to reward the player with 2 Power Scrolls, making it a very lucrative level. These scrolls were removed with the rework of timed doors. To compensate for this change, the scroll count was changed from 3 Power Scrolls/2 Dual Scrolls to 5 Power Scrolls only. Thus, the Sepulcher remains the biome with the most guaranteed stats in the game.
 * Before v1.5, the Corrupted Update, the Hayabusa Boots were exclusive to this biome, and they could only be obtained in the room where the Explorer’s Rune is currently located. Additionally, this room would continue to appear even after the blueprint had already been obtained. As this room has been repurposed for a rune, the blueprint can now be obtained outside the Sepulcher from any Dark Tracker, but only with a minimum difficulty of 1 BSC.
 * This does not affect players who have obtained and turned in the BP prior to this update.
 * Before v1.7, aka the Bad Seed DLC, Cleavers could only be found exclusively in this biome. This marks it as the second enemy to lose biome exclusivity, with the first being the Slammer.
 * However, if the player does not install the Bad Seed DLC, this enemy would still technically count as exclusive given that there is no other way of finding it.
 * With v1.8, the Bestiary Update, this biome gained a new unique enemy, which is the Corpulent Zombie, as the Cleaver became semi-unique.