A piece of knowledge he gives is "The Hottest Item On Sale" (aka) "Drieghan's Ritual Tools" and you need 100 Amity for that. Still have not figured out the Amity game with him. Maybe someone else will but his interest knowledge is "Drieghan Adventure Journal II" and the list is 50 pieces. I only have 28 of it so far.

dont waste ur time, just wave, it's just 100 amity