I know it takes a rune to banish Thul Saduun, but does the N'Gaa dagger (clearly with the presence of Robert Craven) works too to kill it? I suppose yes, but I'd need a confirm...
All monsters can be killed/banished with the dagger while Craven is present. Thul Saduun is different in another way - if looking at the other way to get rid of monsters: While you just have to possess the respective items to kill/banish all monsters but Thul Saduun, you have to spend the rune in Thul Saduun's case.
Sebastian Rapp / Kosmos