twofalls
DM Beadle
I'm idea mining here. A while ago I put up a thread asking for ideas on how to challenge my adventure group as they infiltrate the Zhentarim Stronghold of Darkhold. I recieved several ideas that were very cool, one being a beholder who wears a monicle of Truesigt over one eye working as a doorwarden. Another was approaching the Stronghold from the underdark, which I am going to use, to bypass some of the more pesky aboveground defenses, like the Zhentish army camped around the fortress. 
I'd like some ideas on enchantments to lay on the fortress. Here are a couple I've thought of or have had suggested to me,
Teleportation redirect - to a 40' pit that drops the PC's into a magic dead zone if they try to teleport into or out of the fortress. They have a friendship charm bracelet... think that should work the same way?
Perm Glitterdust/Fey Fire - any invisible creature in the fortress is automatically affected by a glitterdust effect until the enchantment is dropped, and then is affected by Farie Fire for 1 hour per level (dispel at 18th level).
Walls Immune to Transmute/Desintigrate spells.
Magical Tracking team situated inside fortress to hunt down suspected intruders... what would such a team be composed of?
The underdark route is going to have to be clever... as all Underdark access points are tightly controlled. I'm thinking of having the PC's meet an NPC who has an agenda... he wants to free his demon lord master from a prison in the underdark. One of the PC's is exaulted, so he wont tell them his masters true nature'. This NPC will however promise them help if they assist him by telling them how to contact the shade of Lord Gusban, a Hill Giant Chief who once ruled from Darkhold. He will claim Gusban knows a secret and undiscoverred means to access the fortress dungeon. Ideas? Suggestions?

I'd like some ideas on enchantments to lay on the fortress. Here are a couple I've thought of or have had suggested to me,
Teleportation redirect - to a 40' pit that drops the PC's into a magic dead zone if they try to teleport into or out of the fortress. They have a friendship charm bracelet... think that should work the same way?
Perm Glitterdust/Fey Fire - any invisible creature in the fortress is automatically affected by a glitterdust effect until the enchantment is dropped, and then is affected by Farie Fire for 1 hour per level (dispel at 18th level).
Walls Immune to Transmute/Desintigrate spells.
Magical Tracking team situated inside fortress to hunt down suspected intruders... what would such a team be composed of?
The underdark route is going to have to be clever... as all Underdark access points are tightly controlled. I'm thinking of having the PC's meet an NPC who has an agenda... he wants to free his demon lord master from a prison in the underdark. One of the PC's is exaulted, so he wont tell them his masters true nature'. This NPC will however promise them help if they assist him by telling them how to contact the shade of Lord Gusban, a Hill Giant Chief who once ruled from Darkhold. He will claim Gusban knows a secret and undiscoverred means to access the fortress dungeon. Ideas? Suggestions?