Opening the LairEdit
To open the lair, one must destroy some Creeping Nightshade vines that are blocking the path. To do this, it is necessary to gather a Bottle of Naphtha from the bottom step of an altar around 32300,24700 in Black Crag. Use the Bottle of Naphtha with the vines targetted and the vines will be burned down and the bottle will disappear from your inventory.
Within the LairEdit
The lair itself contains a number of R40 Champion Nurglings called Malachian Nurglings and a number of R40 Champion Plaguebearers named Servant of Decay. They are not very strong individually, but if the Malachian Nurglings get a chance to swell and explode they will deal over 2500 aoe damage all at once. After you fight your way through these creatures to the back of the cave, you will find a path winding back down under the cave you have already crossed and Malachia can be found down there amidst a number of Corrupted Wyvern Eggs. Malachia is a R40 Hero Wyvern.
A. If a person is standing near any of the eggs it raises Malachias hate towards that person. You will recieve a white buff/debuff icon indicating that you are standing too close to an egg.
B. Killing an egg causes it to explode and do 3k damage.