Defeat Bloody Vespers and Bloodsucking Vespers around the Altar of High Castor to collect vesper's cells. Then, talk to Luis Garcia at the Cave of Altar. Use your quest tracker to see your progress.
Luis Garcia: Hey, hey, wait a minute! NakanoAzusa: A civilian? What's wrong? This place is dangerous. NakanoAzusa: It would be better for you to leave this place. HiiragiKagami: It's filled with horrifying monsters Luis Garcia: I can't. You wouldn't know how hard it was for me Luis Garcia: to get here. If you do, you wouldn't say that. NakanoAzusa: What would be the reason that makes you want to NakanoAzusa: stay here? Luis Garcia: Seek for the truth. HiiragiKagami: The truth? Luis Garcia: The truth isn't about Trey Songz having ripped body and Luis Garcia: being able to sing and allure all the ladies. I want to Luis Garcia: know every discipline of scholarship out there in the Luis Garcia: world. NakanoAzusa: What in the world? Luis Garcia: I heard vespers inhabiting around the Altar of High Luis Garcia: Castor use strange supersonic waves. NakanoAzusa: That I know. They look pretty similar to both pigs NakanoAzusa: and bats, almost undistinguishable. However, they NakanoAzusa: use strong supersonic waves. HiiragiKagami: I thought my ear drums were going to get torn! Luis Garcia: That's why I have a favor for you. I really want to Luis Garcia: know how the body of vespers is structured. But as Luis Garcia: you see, I'm weak and don't even have a weapon. For Luis Garcia: the advancement of academics in Lakia, could you Luis Garcia: bring one for me? NakanoAzusa: Okay, I'll grant your wish since I've never been a good NakanoAzusa: student. I want you delve into the world of NakanoAzusa: academia on behalf of me.
Reminder Dialog
Luis Garcia: If you get hit by vesper's odd attack, you get Luis Garcia: paralyzed!