barsoomcore said:
There's a fine line between creepy and ridiculous. Just ask Sam Raimi.
I find that suggestion always works better than revelation. Having live people who have gone mad and can only tell the party limited things is really effective -- let them use their imagination. What they are picturing in their own heads will scare them far more than what you describe.
I'll agree with
baroomcore, why try to guess at what your players find the most horrifing, let
them do all the hard work/imagining
I like the idea of the Necromancer being a 'gentleman' and suave, the perfect host. It'd just creepy when your foe is nicer than you.
You could wait till the party is at least slightly split-up (and they
always split up!) and have one or two of them hear what they think is a faint scream or moan, yet they can't seem to find precisely where it's coming from. And of course when they try to get the rest of the party to help there isn't anything to hear/follow.
I'd suggest using furnature constructed from bone(s). Doesn't have to be disgusting or blood-splattered, just made of bones. How would you like it if you were seated at a table and sitting on chairs constructed from skeletonal remains, perhaps even of sentient beings? Waste not want not, and Necromancers certainly aren't squeemish about the dead.
Speeking of non-squeemishness, how about Zombies or Skeletons as servants in the castle? Why pay potentially disloyal people when you have eternally loyal undead? Also makes the PC's decision to attack thier host more difficult if they've seen Zombie Ogres or what-not shambling around the grounds.
One specific bit of 'furnature' I thought would be at least 'nifty', if not really too terrifying unless the PC's realise how powerfull the Necromancer must be to 'waste' undead like this, would be to have an Animated Skeleton of a Giant Snake of some sort suspended from the ceiling being used as a movable light source. As their host is showing them around he can neglegently order the snake to show-off some bit of sculpture (of bone?) that he's particularly proud of, thus suprising the characters.
Hatchling Dragon