I'm just starting lightless depths and I have a party that has just begun to make use of the wind walk spell. They have killed Igirzid and are planning on descending into the underdark and exploring it on their own via windwalk.

This of course has pros and cons, but it will enable them to bypass a few encounters, and I would like to give them a few challenges and the chance to earn some more xp before they hit Golismorga. Any suggestions for cool underdark encounters that could work well against a party of wind walkers. They will be quite visible because the party has an abjurant champion who uses the luminous armour spell and radiates light.

I had been thinking along the line of a dead magic zone and some cave trolls, but maybe that's just too cruel.

Well P.H., since Wind Walk is basically 'Mass Gaseous Form' with the added bonus of a 600ft fly speed (at POOR maneuverability), they have all the limitations and advantages of gaseous form. Not counting the one character being a self-propelled glow-lamp, they are not invisible - they "appear misty and translucent". Even if fully clad in white (a highly unlikely thought to most players) that fog is blitzing through the environs at literally 100ft per second is going to come across as a tad ... obvious, shall we say.

Also, it takes 5 rounds for the change in form to take effect, not to mention that the last 10 rounds (minute) of the duration translates into automatic descent.

Also referencing Gaseous Form, they cannot bypass liquids (water) nor solids that are not cracked or otherwise permitting gaseous form to seep through. They are bereft of thier presumably higher ACs (no armor/natural armor), although the benefits of gaseous form arguably make up the slack.

If you just gotta whack-a-mole 'em, they will be at thier most vulnerable if they wisk through at high speed into a solid body of water. Insert aquatic critters o' death at your discretion. :)

Well since they are going into the underdark create yourself a nice drow patrol and when the drow wizard makes a spellcraft check, reconizes the spell he fires off a dispel magic and watches them fall from the sky. Would that work??

It would work, except that there aren't any drow in the underdark under the Isle of Dread. I mean I could change that, but it wouldn't really fit with the campaign.

Well since they are going into the underdark create yourself a nice drow patrol and when the drow wizard makes a spellcraft check, reconizes the spell he fires off a dispel magic and watches them fall from the sky. Would that work??

Could have the Taloc Tear' wall stop them.

You could just let them do it. Reality is if they skip encounters they face harder ones later with less treasure. There is nothing really secret in this place so you don't actually loose much from letting them use the spell. Its possible that there are the odd creatures on the way down that can interact with them but if not well no real harm done.

Hopefully this will get the whole idea out of their system before they try it somewhere where it would become a real strain on the the plot line if they start zipping jumping past encounters.

Jeremy MacDonald makes the best point of all.

Let 'em - just familiarize yourself with the geography ahead of them, then let the dice fall where they may. Sniffing ahead via wind walk is not necessarily a bad thing in principle - and doing so all together is good on thier end. But, if they skip ahead to certain points and find themselves hip deep in kimshee ... well ... oops.

Kudos Jeremy!

My players use it with invisibility all the time. Naughty combo... This made us propell through a few encounters but still, they had to turn back into corporeal once they wanted to fight or cast spells.

I am having the same issue with City of Broken Idols, the party decided to Wind Walk over the main island to scout it out.
After one Demon ambush when they de-cloaked, there are plenty around to spot them flying around, they stopped doing that.

I think I'm going to run an enocounter with a group of trogs returning with a new shipment of shadow pearls. It's been about 3-4 months since the battle of Farshore, which is enough time for another batch to be ready.

I've also expanded on Loagrot by addding in a lower level, where they store the shadow pearls and where their high priest stays. I'm thinking that the trogs may be allied with a deepspawn that lairs in this lower level and possibly guards the shadow pearls. The thing has ingested some digesters over the years and likes to spawn them, so the trogs have a small supply of digester pets that will help guard this level.

For the encounter in the underdark I'm thinking:

8 trog lepers
2-4 digesters
1 10th level trog favoured soul (featuring silent spell feat, and various spells from book of vile darknes- Heart Clutch, Flesh Ripper and Wither Limb being my fav selections for the range he would have accces to)
2 arrow demons
handful of zombies or skeletons that carry the pearls.

The party will want to stop these guys and will certainly engage them.

Heh... That wouldn't work in my Isle of Dread. I wanted to keep the nautical theme, so I changed it so all of the tunnels are partially filled with water winding slowly down hill and warm sulfury (volcanic) air always streaming up (inspired by one of the rumors in the player's guide). They are exploring with long boats.

As a bonus, I can't see Wind Walk working for anything but going up with the constant wind... :)

Heh... That wouldn't work in my Isle of Dread. I wanted to keep the nautical theme, so I changed it so all of the tunnels are partially filled with water winding slowly down hill and warm sulfury (volcanic) air always streaming up (inspired by one of the rumors in the player's guide). They are exploring with long boats.

As a bonus, I can't see Wind Walk working for anything but going up with the constant wind... :)

I suppose you can rule however you desire but the spell says that a magical wind is generated when they want to go fast. Their relying on their own magical power source to move.