Loot a R'Jhere's Severed Hand from the corpse of Head Archivist R'Jhere. Use the hand on a braizer at ( 0, 7, -290 ) Copy/waypoint 0, 7, -290 to summon the ghostly Mayong Mistmoore.
Equip and use the Illusion of the Head Archivist and then talk to Mayong Mistmoore. This will unlock the chest further on in the zone.
Note that anyone talking to the ghostly Mayong without the effect of the robe will summon a repository guardian.
Open the chest at ( -87, 17, -364 ) Copy/waypoint -87, 17, -364 to get the Ankh of Ydal and complete this step. The previous two steps are silent updates, and only one person gets the hand or robe so they must coordinate to unlock the chest. The chest will update the quest for everyone in the group, however.
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