"Necropolis" - changes to creatures of levels 6-7.

I was thinking about something, and I've suggested this before, but I remembered the campaign featuring Arantir (the first scenario with him), and there were Death Knights in the hut. Now, there are neutral dragons, but it would be great to put those Nazgûl (sorry, I forgot their name in the mod) in that spot. So, we'd have: Astral on its own, with incorporeality, and in the place of the Death Knights, we'd have a spectral unit with a rider and a deadly strike. There was a dialogue in the hut, and if we play the campaign with these mods, there won't be any inconsistencies, and the Nazgûl would look great.