Hi, the first time I played through this game I did so without any expansion packs, and Lord Dredmor was on level ten.
This time I have the diggle expansion pack, and I have searched every room on level ten and he is not there. Does he spawn on a different floor with an expansion pack? Is it possible for him to not spawn at atll? And is it possible that there is a completely closed off room somewhere on the black edges of the map that can only be accessed by a red portal?