Which one is the third? I've done Belurat and Castle Ensis (if it counts?), only just started poking around in Shadow Keep but it looks absolutely wild so far. I also made it to the putrescent knight's arena but I've not tried actually fighting it yet, just jumped in once to see what was going on at the end of a session
The knight was pretty brutal, but fortunately this run has been my "learn to parry" one, so I came basically perfectly equipped to fight any player-model enemy that isn't using colossal weapons