From HGWiki

See here Shadow Pontiff for answers on how to open the first door and what to gives the relevant items to to spawn Ruination who then drops an item to allow access to the door at the end of the area. Ruination casts multiple Greater Ruins (DC 35 versus fortitude) and various other spells. The second door requires you place the seal obtained from the priest in the shadow elves area and the skull you find here be placed on the altar. Note: The doors in this area can be 'twitchy' and close locked so make sure you get through them before this happens or you will have to retrieve the keys again. Beware of using loot-breaking spells on the Shadow Orbs in the room with the giant statues as this will break the items on the table needed for offerings.

Rest Spawn Chance

Zero

Creatures

• Arcane Spectre
• Greater Shadow
• Ruination the Lich
• Living Darkness
• Poltergeist

Exits

• The Dead Wood
• Morgue of Darkness