DM needing advice for the Age of Worms

[Zid]

I´ve played the Age of Worms campaign path with my gaming group the last few months (spoilers below).

The group is right now playing through the prince of redhand, and consists of the following

Druid 16 (with summoning feats and spends most of his time shapeshifed into a dire tiger, complete with wild armour)

Cleric 7/Radiant servant of Pelor 9 (complete with Knight 13 cohort and improved turning. No DMM cheese though)

Sorcerer 7/Incantrix 9 (the real "trouble" of the group, often sendning both twin enervation and quickened disintegrate at enemies)

I´ve recently thought that I am having much more trouble challenging the party. Yes, I know that they are all full casters, and that I have two CoDzillas and one batman/Incantrix gouda, but that´s the way my players want to play.

Recently, they met the advanced aspect of the ebon triad in the well of Triptych knowledge. It managed to take the knight to 2 HP, and the cleric to somewhere in the low twenties, but then it was taken down by the multiple enervations (13 negative levels) and disintegrates of the sorcerer.

The only real trouble they had the last few adventures were with the swords of Kyuss, and their invocations of the worm.

The following are the main problems:

1) The group has extremely high AC, all of them. They use buff spells to great effect.

2) The cleric can easily improved turn most undead encounters.

3) The sorcerer is constantly flying, invisible, mirror imaged and greater mage armoured.

I want to challenge them in the upcoming adventures, NOT TPK them. The next adventure is the library of last resort. The BBEG of that adventure, Darl, is a cleric 18 of Vecna, that will know a lot about the party. How would he prepare? Any other general suggestions to how I can tailor future encounters to challenge them? Should I just increase the ER, since they are playing very optimised PCs?

Thankful for any ideas.

/Zid

[Sstoopidtallkid]

Greater Dispel Magic and a Cohort with a ring of 1 per day AMF. That will take the party a bit better.

[Kizara]

Use AMF and good melee allies, then you problem is mainly the druid and his animal companion. Still, AMF shuts off the sorc problem and most of the cleric one.

Honestly, AMF is an extremely reasonable obstacle/ability at these levels.

What kind of melee allies? Iron and higher golems. If they get around the AMF, there's still the golems.

Other ideas: barb/hexblade/FB/occult slayer with items that grant him true seeing, flight, strength boosts, death ward (seriously? level drain, there's tons of defenses against that at these levels) and freedom of movement.

Groups of Greater Shadesteel Golems (MM3) these guys are NASTY.

Also, the druid's companion is an animal, which is auto-defeated by certain undead fear effects. Make sure to include that, even if the cleric dusts it (he still he to take an action to do so).

Pepper your PCs with targeted Greater Dispel Magics. Whether its a caster with a staff, some kind of trap-item, a spell like Wall of Dispel Magic or a creature that has it as an at-will SLA, just dump it at them constantly.

Use Unhallow with Freedom of Movement to stop most of the battlefield control stuff that will shut down the cleric's minions.

Big, fat advanced elementals that have death ward and freedom of movement cast on them. Assloads of hp, lots of attacks for good damage (advance them until they hit OFTEN for LOTS of damage).

(You're allowing Monk's belt cheese for their ACs to be so high, aren't you? I honestly don't think that item is meant to work that way, after re-reading it a few times. If it was meant to give a bonus that powerful you think it would come out and say that.)

Use typical clericy CL boost cheeses (Divine Spellpower, necklace of prayer beads, ioun stone, ally casting Mystic Surge) to boost the cleric of vecna's CL enough for Blasphemy to do its work. Really, if your PCs die to this they should have had better defenses at this level and power level of a campaign.