Since buying it, we've been playing #Karak a lot. So it made sense to buy the expansion, called Regent: https://www.albi.eu/en/karak-regent

New heroes. The "listening ahead" mechanic is a bit awkward to handle (one player secretly looking at drawn tiles). I like that they tried to make the dungeon itself more interesting with special tiles. Torn on the duel aspect. It warps players through the dungeon. It can balance, but usually just makes strong players stronger. Overall worth its money.