Below is a walkthrough for the Thanks to a Comrade 2 subquest in Valkyrie Elysium.
Obtained: Speak with Eygon in Valhalla after completing Chapter 5
Objective: Purify the Undead
Head through the city making your way to the cathedral. On the other side of the cathedral, use the Soul Chain to reach the other side. Defeat the enemies on the northwestern side of the courtyard to trigger a cutscene. When it concludes, the quest will clear!
Rewards:
- Meteor Swarm II
- Full Impulse
- Instant Sunder