I must say that I did not like Dark Brotherhood in Morrowind... Camonna Tong for ever. Too bad that was one of the few factions that player could not join (I don't see a reason why Dark Elves cannot join Camonna Tong).
But about the Morrowind, whole Crassus Curio thing was the most ridiculous and funny line of quests ever (I literally jaw-dropped when I was playing back in 2006 and I had to... undress for him and give him a kiss... LMAO). Bethesda, why do not make more characters like that?
