|Main music||Undead Dungeon|
|Strongest monster||Tarn Razorlor|
|Quests||The Lair of Tarn Razorlor|
Tarn's Lair is a complex dungeon full of undead located in south-western Morytania. It is an ancient temple with unknown origins, the entrance to which is found in the Abandoned Mine. To get there crawl into the cart tunnel and head north. Completion of the Haunted Mine quest is required to access it.
It is the main base of operations for the insane human necromancer Tarn Razorlor and his undead minions. He had travelled to the area seeking a way to gain more control over the undead, and by enchanting the salve crystals found in the nearby mine and making a pendant from it, he was able to do so.
The main attraction of the lair is The Lair of Tarn Razorlor miniquest, where players encounter Tarn Razorlor and fight and kill him. After the miniquest is completed, players are rewarded with the salve amulet (e) and the ability to fight Tarn's pet terror dogs, which may be assigned as Slayer tasks.
The entrance to Tarn's Lair is at the northern end of the ground level of the Abandoned Mine.
- The fastest way to reach the end of Tarn's Lair is with a ring of slaying, which can be purchased from a Slayer Master or crafted by the player.
- Drakan's medallion will teleport players to Burgh de Rott, where a shortcut over a fence to the west leads to the mine.
- Taking the shortcut under the Hair of the Dog tavern in Canifis and travelling on the Swamp Boat brings players close to Mort'ton.
Tarn's Lair has three levels, with stairs and passageways connecting them. There are many traps and two ways to deal with them; slowly disarm each trap, or ignore the traps and take the damage.
Odovacar is the only banker in the area, and charges 100 coins each time you use the bank. With the addition of the money pouch, the coins will automatically be taken from your pouch when you select the bank option. This bank is not a safe area and will not heal you like other banks.
If you do not have 100 coins with you, some of the undead in the lair drop coins. It is also possible to access your Grand Exchange collection box for free and get 100 coins from there.
The player starts out on the lowest level, where the banker is to the north-east. Follow the dotted green line on the map to the right. To get there:
- After entering the lair from the Abandoned Mine, go east past the floor traps, wall trap on the north wall, and monsters to the end of the passage.
- Head north, turn east, then follow the path heading north again. There are two wall traps to disarm (by "searching" them via a right-click option): the southern one on the western wall, and the northern one on the eastern wall.
Odovacar is at the end of the corridor. This is the last place to restock or heal prior to moving to Tarn Razorlor (though there are a few safe places to rest along the way).
- From the banker, go north through the passageway.
- Follow the U-shaped hall all the way to the end, past floor traps, wall traps, and monsters. Take the western doorway.
- In the square room with a single giant skeleton in it, go through the passage to the north.
- In the following room, go through another passage to the west.
- You will now be in a hallway that looks like an inverted T. Take the passage to the north, avoiding the wall traps on both sides of the wall, and go through the doorway on the west side.
This puts you in a room with pillars that you must jump across and a log trap you must disable. There are no monsters here, so use this room to heal if necessary.
- Make your way to the west side of the room using the southern pillars and deactivate the log swing trap by searching the button on the floor. The trap will eventually reset, so move quickly.
- Use the second row of pillars from the west to go north.
- Follow the path to the east, past wall traps on the southern and northern walls, and you will end up in a room with four walls that shoot out periodically. Time your moves to avoid being knocked into the hole.
- Take the passageway through the eastern wall.
There are more pillars to jump over; the correct route zigzags across the room from the north-west to the south-east. You will be attacked by two level 94 skeleton mages as you cross the room.
Once across, go down the stairs into an empty room, which leads to the final rooms to the north with Tarn Razorlor and his terror dogs. This is where the ring of slaying's teleport leaves players, and can be used to prepare for combat.
At the northern end of the next room is the entrance to Tarn's living quarters, where Tarn's diary sits on a table. If players bring a salve amulet, it can be upgraded to a salve amulet (e) by using the amulet with the diary.
- With the release of Tarn Razorlor and his lair on 22 January 2007, all skeletons, ghosts, zombies and most undead creatures received a graphical update.
- Players used to be able to use a ring of slaying to teleport directly into the end of the maze just outside the boss chamber, regardless of whether or not the miniquest has already been completed.
- Next to the Toad batta spawn is a Gnome skeleton, which has the examine text of "Look's like one of Gianne Jnr.'s deliveries didn't make it on time."