lol..i kinda cheated by reading other forums..but you need 1)salt:in the kitchen 2)Coal: where you fought Fergus 3)Sulphur: w/ that gay medical guy..lol it's in a little tray thingy on a table or something

First mix the salt and coal barrels together...then add the sulpher to that mixture and voila! Instant kick-a$$ citadel explosian!