You have been most helpful to me, $N.  I would like to reward you with the very recipe for the brew I gave you earlier, but I must ask of you a favor that is quite dangerous.$B$BThis lockbox contains three empty thaumaturgy vessels; they are imbued with an attunement aura that will drain the blood of a scorched guardian dragon.  Using one on the beast will anger it greatly, so be careful.  Once you have all three filled, bring them to me.$B$BDo this, and the recipe will be yours.