Wardens of the Dream

After killing Jammal'an the Prophet and Ogom the Wretched, Dreamscythe and Weaver will spawn in the central room, and the Shade of Eranikus will become attackable.

Adventure Guide
''Four promising young drakes accompanied Eranikus into the Temple of Atal'Hakkar, eager to prove themselves by serving a great and powerful wyrm. One by one, they were captured and tainted by the Emerald Nightmare, and they now wander the halls of the Sunken Temple, lashing out at all who intrude upon their waking dream.''

Strategy
Before awakening the final boss, you'll have to defeat his children, four large green dragons. If not killed, they will join the fight later on. First, take out Dreamscythe and Weaver, pulling them back to a spot away from other dragonkin. Keep these drakes turned away from the group, as they have acid spit that can spread across all five members. Through hallway to the south, the final boss is protected by two more large drakes, Hazzas and Morphaz.