Story related, can't be missed.
After completing enough Wyrmhunt quests from Maximilian (I think it's two), you are offered a chance to see the Duke. You cannot complete any further Wyrmhunt quests after seeing the Duke, so finish up what needs finishing or lose the chance later!
Simply accept the option to "Hear the Duke's Directive" and after a few "are you sure?" sorta question, you'll be allowed to enter the Dukes Demense, see the Duke, and (after the fool's shenanigans) this achievement will pop.