Hunt Merkbees around OvervoldFarm to collect Pieces of Caelium. Take these to Merchant Hernan at Overvold Farm. Use your quest tracker to see your progress.
Merchant Hernan: Feel free to bring me more pieces of caelium until you Merchant Hernan: get stronger. It's a good deal for both of us! Honest!
Reminder Dialog
Merchant Hernan: Not all merkbees have the same amount of caelium. Merchant Hernan: Some don't even have enough to collect. Keep Merchant Hernan: looking, though, and you'll have enough soon!