Defeat Ovises to obtain Ovis Necklaces. Defeat Maleyes to obtain Maleye Cores. They're both at Algon Market. Then talk to Captain Diana at the Algon Post. Use your quest tracker to see your progress.
Captain Diana: The dark energy spreads. Can you feel it, Aitan? NakanoAzusa: Yes. The other soldiers seem very tired. Captain Diana: Aitan have the strength to press on in times like these, Captain Diana: but normal humans are very strongly affected by this Captain Diana: energy. HiiragiKagami: Is there any way we can help? Captain Diana: If memory serves, there is an alchemic solution to the Captain Diana: problem. It ties in with the theory of the homunculus Captain Diana: and how the Algon controlled the ovises. NakanoAzusa: What do I do? Captain Diana: If you can retrieve for me necklaces of the ovises and the Captain Diana: cores of the maleyes, I think I'll be able to Captain Diana: extract the magic from each and create a small barrier Captain Diana: around the necklaces to fight against this dark energy. NakanoAzusa: I'll get the materials!
Reminder Dialog
Captain Diana: I'll get ready to perform the necessary ritual.