Wartales

This achievement is for completing the side quest “Legendary Creatures” in Drombach. It’s just a regular optional mission, not tied to the scenario objectives.

You have to go to the Sophy Adr Alazar Laboratory and talk to Professor Maurith. She will send you on a self explanatory fetch quest to dig up dragon bones in:

Great Growler Grotto (Arthes)
Fatclaw Cave (Ludern)
Great Growler Cave (Grinmeer)

Afterward, return all the way back to her and you’ll have to Threaten her to complete the objective.