History of Coup de Grâce

Overview

Coup de Grâce is the final Story mission of Season of the Hunt, set in Harbinger's Seclude in The Dreaming City. In-game description: hunt the High Celebrant of Xivu Arath into the Dreaming City. Recommended power is 1250 (the mission is unlocked through the season's campaign after "Trail of the Hunted").

Walkthrough / mechanics

1. Track the High Celebrant with Crow and Osiris. It slips between the physical world and the Ascendant Plane.
2. Use the Cryptolith Lure to weaken it. The goal is to kill it in the Ascendant Plane to strike a blow at Xivu Arath's forces.
3. Destroy the residual energy trails to reopen the portals as it hops realms; it also raises immunity shields mid-fight and tries to flee through portals, which Crow's intervention prevents.

At launch, killing the boss too fast could break the mission; Bungie advised slowing down and waiting a few seconds before shooting the black blight orb. This was a launch-era issue and may be fixed.

Rewards

A weekly pinnacle-style reward and a chance at the exotic ship The Fourth Mark were reported at launch (GamesRadar summary); not verified against current data.