From HGWiki

Cave Trolls live here and it is also the lair of the Spawn of the Deep One (level 25 accomplishment (see Accomplishments)), true seeing is required here if you don't want to be in permanent darkness. Kill the cave trolls to meet the KC requirements for the dragon.

Rest Spawn Chance

Zero

Creatures

• Cave Troll
• Cave Troll Shaman
• Rogue Spectre
• Spawn of the Deep One

Exits

• Hall of Statues
• Cave Troll Lair
• Caverns of Underdark