Below is a walkthrough for the Thanks to a Comrade 3 subquest in Valkyrie Elysium.
Obtained: Speak with Eygon in Valhalla after completing the Thanks to a Comrade 2 subquest.
Objective: Head to Be’elze Castle
Follow the objective a short way to trigger a cutscene leading to a boss fight against a harder version of Naglfar Eygon. Defeat it to clear the quest.
Rewards:
- Meteor Swarm III
- Meteor Swarm
- Vertical Edge