Demon Gnome said:
My original plan was to run the PC's through A, B, C, M, N, but they have been through much of C and haven't leveled as far or as fast As I planned, and so I decided to slip in an extra lvl 7-9 region, namely I as it ties in with M. Not to mention I just looks so freaky it'll be fun. They are going to regret their lack of a healer once they start becoming diseased. Unlike region A when they were last diseased they can't just rest somewhere and wait it out as many rooms in I will simply aflict you with thre same or new diseases again =P.
jim's got some good percentages going there - the Southern Halls are covered in all forms of noxious goop, living and otherwise, that could conceivably prevent the passing through walls bit.
As for the lack of a healer...look through the intro to I
carefully - they're going to regret getting injured at all. Healing won't be a problem, no sir. Just, y'know, ignore that weird skin color...or the scales...or the slime.
On the GMing front, I very much reccommend emphasizing the sheer
wrongness of I - Mahir and his cronies were experimenting with Magic Mortals Were Not Meant to Know, and it shows here. The enemies, tactically, don't have to be relentless - have them retreat at half HP, only to reappear later, changed by the trapped magic/positive energy in the Halls. Things there drip, they spurt, the dribble and run. Everything is wet, hot and close.
The contamination in I seeps into everything, in little ways. Got leather goods? Have them bloat up, grow pale, warm...is the leather alive, or is it just magic? The PCs' belongings won't attack them (probably), but there's a ton of nice touches that can be used. Follow the tryptych of good horror - terrify, horrify, then gross out, in that order. By the time the PCs get to Siglinde or the drow, they should seem a relief by comparison to something like Madness or Anguish.