You mean the entrance to the Necropolis? You can access it from you Quest Log (the treasure chest icon) or you can travel there by Falconreach Gryphon.
In Doomwood, or you could just travel to Necropolis/Doomwood via the Gryphon (Click the sign next to Ash and then Travel)
You need to completely unlock Paladin and Necromancer armors before Death Knight class is available to be used. It is explained in game by Artix (in Doomwood/Necropolis)
the answer is doommod44556 i don't know if it is doomwood or chaosmod44556
Death Knight armor is unlockable from Artix in Doomwood/Necropolis, after you complete the quest chain. You will need to have unlocked Paladin and Necromancer first, the Death Knight armor is trained in the same way.
You can buy it from Arryd in DoomWood forest (/join doomwood) for 10750 gold.
go into Oaklore, and to the second door from far right actually its the door with the candle icon above it on the left
You can find him in the last room (go to the red door) and that's where you find him then you have to chase him around
It's in Amytivale. go all the way left. you need a DA though.
in doomwood
you can get it at Doomwood
Reach rank 4 in doomwood and buy it from the Doomwood Rep shop accessed from Lady Speedstyk in Lightguard for 15,555 gold.
The mausoleum in AdventureQuest Worlds can be found in the Doomwood area. It is located to the left of the screen as you enter Doomwood, near the cemetery gate.