Guardians can earn the Ritual Under Shadow Triumph in Destiny 2's Season of the Haunted, by hunting down the Nightmare of Sy'ad, the Unending. He is an elite enemy that must be defeated as part of the Reaper title. The in-game description of the Triumph reads, "Clear the Haunted Alcove passageway containing a Nightmare ritual." Sy'ad, the Unending's Nightmare can be found in the Royal Pools, onboard the Derelict Leviathan.
The ship can be rather confusing to navigate at times. Those having trouble finding the Royal Pools can travel North from the Castellum Landing Zone. Taking a left from the third unlit brazier will lead to the main entrance of the area. The Haunted Alcove can be found by heading through the corridor and continuing directly North. The location is west of the Nightmare of Qalec, the Sniper in Destiny 2, and is marked by corrupted tendrils. The enemies inside are not always present and will take time to respawn after their defeat.
Related: How to Complete the Nightmare Breached Triumph in Destiny 2
Unfortunately, Guardians must wait for the Nightmares to return. In the meantime, plenty of other events occur in the Royal Pools. Once the message, "Dark Ether thickens in the air..." appears above a player's abilities, a Nightmare Lurker will take post near the entrance to the Haunted Alcove. Further inside, other Nightmare Scorn will continue to spawn. Sy'ad, the Unending is a Nightmare Abomination that can only be summoned through a ritual.
Inside the Haunted Alcove, there are three Ritual components that need to be activated. Before summoning the main target of the Triumph in Destiny 2, Guardians are advised to take out the lesser Nightmares. This will prevent players from being overwhelmed with enemies,
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