I'd like help from the collective smarts of all readers. Help minions of this super-intelligent BBEG with nearly infinite resources and access to all Arcane and Divine spells set a really nasty ambush for outrageously powerful high level PCs.
Spoiler:
Ambush point is a 'safe refuge' the PCs left and will likely return to very suddenly by teleport. There's a horrendously huge and nasty ambush in place that has a good chance to be a TPK. The ambushers will probably have 2 round advance warning before the PCs arrive. It's a very powerful party & the players have asked for danger and challenge, so please help increase the chance of TPK.
One layer of the hoped-for PC-massacre is a layer of flying incorporeal undead. Shadows seem to be most effective, not the more powerful spectres, because every touch attack automatically does 1d6 STR damage, no save. These PCs pretty much only fail a save on consecutive natural ones.
The nasty villains setting up the ambush bring in a crowd of 500+ ordinary small slaves. The area is Desecrated, as the spell. The slaves are rendered helpless & locked in a room, then a Greater Shadow (under the control of an NPC cleric) kills all 500 slaves, causing them to ALL become shadows. This pack of 500 shadows swarms the area, with most hanging out with the Greater Shadow inside 40' of rock. The Greater Shadow will release them on the PCs in groups of 50-100 after the initial 200 swarms them. Best (worst!) case each PC can be attacked by 26 shadows, each a touch attack that drains STR. That's 9 from above, 8 around, and 9 from below. Even hitting only on a 20 that's about 1d6 STR drain per round. The PCs will need to pump out a weak (probably Quickened) point-blank fireball every round just to keep the shadows off.
Just for fun they also animated hundreds of the corpses as a variety of lesser undead. Mostly Burning Skeletons.
The NPC assassins are mostly protected against their own undead, although accidents happen.
So, given immense resources (no wishes, etc without a darn good reason) and access to all spells, what layered magic nastiness can be set up? Ideally stuff that will weaken the PCs. Best options are things that inflict a penalty even on a successful save, and that stack.
Please help me come up with more. Access to pretty much EVERYTHING. Here's my starter list:
Pre-buffs in place
Desecrate - profane bonus
Symbol of Vulnerability (on floor, triggered by PC arrival), foes in 60' have already used Password. 9th level version of Symbol of Death.
Symbol of Insanity.
Symbol of Stunning.
Symbol of Pain
Symbol of Weakness
help me add to this list, pull out all the stops
First round spell attacks:
Dimensional Lock (8th Divine)
Polar Midnight (9th level divine) off a scroll
Help me find 4 more utterly nasty spells, 2 Divine and 2 Arcane, to make life brief for 6 super-duper PCs. 2nd round spell attacks are also welcome. There's a good chance that some of the NPC casters will survive until Round 2, which is unusual when facing these PCs. When considering how nasty to get, consider that the PCs output 1500 - 2000 HP of damage per round.
Specifically looking for help with:
1. Ways to prevent PCs from teleporting away! (not all can teleport, but most can) besides Dimensional Anchor.
2. Ways to multiply effect of the shadow swarm. Most PCs have outrageous touch AC and will only be hit on a 20, so every buff helps.
3. Targeted way to attack a Synthesist Summoner
The enemy will know 2-3 rounds in advance that the PCs are coming, so allow for 2 rounds of casting by each of 6 high level casters right before the PCs arrive. Spells longer than 1 minute/level will already be in place. The actual casters are clerics & wizards, each 12th-14th level, but they can have plenty of scrolls of any spells besides Wish et al. So that's up to 12 spells pre-buffed, 8 Divine and 4 Arcane.
*Starts flipping through book the of evil and "technically Legal" monsters*
Shadow Swarm:
Advanced Greater Shadow Swarm CR 10 XP 9600
CE Fine Undead (Swarm)
Init +15 Senses Darkvision 60 ft.; Perception +18
Defense
AC 34 (+4 Deflection, +4 Dodge, +11 Dex, +8 Size)
hp 67 (9d6+45)
Fort +7 Ref +14 Will +9
Immunity: Undead Traits, Swarm Traits
Defensive Abilites: Incorporeal, Channel Resistance +2
Offense
Speed Fly 40 ft. (Good)
Melee Swarm (1d8 Strength)
Special Attacks: Create Spawn, Distraction DC 18, Strength Damage
Statistics
STR - DEX 32 CON - INT 10 WIS 16 CHA 19
Base ATK: +6 CMB - CMD -
Feats Dodge, Improved Iniative, Mobility, Skill Focus (Perception, Stealth)
Skills: Fly +27, Perception +18, Stealth +31 (+35 in Dim Light, +27 in Bright Light)
Racial modifiers: +4 Stealth in dim light (–4 in bright light)
Languages: Common
Those might be of some use, I would think an enormously powerful spellcaster knows how to tear big shadows into tiny, sentient pieces.
Best of all worlds really, no save, no attack roll needed... *Evil Smile*
You could try putting Unhallow and Forbiddance in place.
Both spells last very long and have little effects.
Unhallow can give each undead another boost. For example Deathward (To block the "Undead to Death" spell. But other options might better (you know them better than I do).
Forbiddance would have to be carefully set up so they don't prevent them from coming here in the first place (leave a small triangular gap by casting it 3 times?).
Then if they take a step and the alignment is different they automatically take damage. And you only need to seal a small area with a lock.
Calcific Touch targets Dex instead of Str and does not allow a save to negate the Dex damage (only the slow effect). You could target a low Dex character with it (quickened and reach'd) so the shadows have an easier time touching him or her.
Lastly... you could focus on counterspelling. You have the numbers advantage and your main problem are area spells. If you focus on simply countering all area spells your enemies will be hosed.
black tentacles might be a good idea...can screw over all the spell casters, and might screw over a few of the others too. Could also have a delayed blast fireball (or two) waiting for them when they appear. "Oh look, we're back."....then Boom!!
Not certain about the GM vs. Player vein here...but I'm sure it is for a story or plot advancement so...
Since the party is teleporting back...fill their Teleport/Word of Recall safe haven with sand?
Word of Rec...WTF? Though I suppose some rules-lawyers may say the party just teleports somewhere else safely (1d10 mishap then 1d20+80 until they get similar location)
Spell-wise?
Time-Stop to stack on even more spells.
Horrid Wilting has always been a high-level favorite.
Planar Binding/Ally works to bring in some truly nasty foes.
As for the synthesist? Heightened Persistent Banish and Dismissal max DC plus Persistent to make the guy save twice and take worse each time. Then bye bye Eidolon armor. With 2 spells that's 4 saves, take worst 2 that the synthesist has to make or be standing there naked.
Really a blockbuster wizard build (or two) will do fine.
Quickened Intensified Fireball (or acid/cold/electric) plus Empowered Intensified Fireball (or acid/cold/electric). With that 1 level dip into cross-blooded sorcerer. And an effective caster level of 15.
15d6+30 plus 15d6+30x1.5. Slap on Persistent (with say a metamagic rod) so they save twice and take the worse save. That's per round.
Per caster. Have a familiar with goblin drums and that jacks up to 15d6+40 each. That ought to make some kind of dent.
Swarm-wise, Hellwasp Swarms are always fun. Especially with templates. Slap on advanced and the apocalypse* templates...plus fiendish/resolute for smite bonus damage
*Starts flipping through book the of evil and "technically Legal" monsters*
** spoiler omitted **
Those might be of some use, I would think an enormously powerful spellcaster knows how to tear big shadows into tiny, sentient pieces.
Best of all worlds really, no save, no attack roll needed... *Evil Smile*
+1. This was going to be my starting suggestion. Why bother with all those dinky attacks when you can just fill all of the space with undead swarms.
Follow this with Gate spells to pull in big hitters who are immune to energy damage.
The arcane casters trying to kill the PCs can only natively cast 7th level spells. Anything higher level must be off a scroll. The scrolls are penned by a 20th level arcane caster. Divine spells are natively limited to 6th - 8th level, with a few higher levels divine spells on scrolls.
The Synthesist is an especially tough nut to crack. The above suggestion of using spells that allow a save is unlikely to work. Chance of success of 4 consecutive saves, failing only on a 1 , is about 82% not counting rerolls. Counting rerolls its more like 98% of success. Instead, I'm thinking an Anti Magic Shell shot into the back of a nearby zombie by an Arcane Archer NPC assassin. That instantly removes the eidolon, no save, for as long as it's inside the 10' radius.
The Shadow Swarm is a great concept, and I might do it. My only concern is that, when standing inside a shadow swarm one only takes d8 STR damage per round. They can survive that for 3-5 rounds, which lets them output 4,500 HP - 20,000 HP damage which will certainly exterminate everything nearby. They have access to Mass Heal and also to many Heal spells. I foresee the Wizard repeatedly filling the space with Selective Quickened Fireballs.
Basically, if the PCs are still standing on round 3 then the ambush has failed and the PCs will win. This is the most likely outcome, regardless of how nasty the GM makes it. I don't think it's possible to TPK this party by inflicting HP damage.
Oh, one of the Round 1 or Round 2 spells will be Disjunction. Like I said, no holds barred. If the PCs win they will get so much loot that anything they lost to Disjunction will be small in comparison.
just to point out that the spectre DC is after 1 day.
Quote:
Energy Drain (Su) This attack saps a living opponent's vital energy and happens automatically when a melee or ranged attack hits. Each successful energy drain bestows one or more negative levels (the creature's description specifies how many). If an attack that includes an energy drain scores a critical hit, it bestows twice the listed number of negative levels. Unless otherwise specified in the creature's description, a draining creature gains 5 temporary hit points for each negative level it bestows on an opponent. These temporary hit points last for a maximum of 1 hour. Negative levels remain until 24 hours have passed or until they are removed with a spell, such as restoration. If a negative level is not removed before 24 hours have passed, the affected creature must attempt a Fortitude save (DC 10 + 1/2 draining creature's racial HD + draining creature's Cha modifier; the exact DC is given in the creature's descriptive text). On a success, the negative level goes away with no harm to the creature. On a failure, the negative level becomes permanent. A separate saving throw is required for each negative level.
so to say that you prefer shadows because their attack doesn't have save, vs spectres because their attack has is a bit eh...
also, energy drain, even if not lethal, will probably cause the players to spend some resources due to restoration having material components (100gp if cast before they become permanent, 1000 if cast after they become permanent)
To start with, I would encourage something a little less straightforward then "kill all the monsters." Something like a rescue, the need to get to a certain point to escape, or securing a keep against the creatures -- those kinds of goals can make things more interesting and lead to a PC strategy more creative than "Fireball everything in sight."
Next, to keep this from turning into a bookkeeping nightmare, I would consider statting the shadows and burning skeletons and anything else numerous using the troop subtype. With all the shadows coming at them, it's going to be easier to adjudicate a troop/swarm of the things than it is to roll for all the horde individually ... and the individual shadows/skeletons aren't going to be able to harm high-level PCs anyway.
Third, consider Control Weather. It's a 10-minute casting time, but nobody says the bad guys have to wait until right before or during the battle to cast it. If the created weather is severe enough, it can force concentration checks on the part of the casters, make it harder for the martial types to move, and make ranged attacks nearly impossible. Additionally, anybody who flies has a chance of getting blown away in the high winds. And I'm willing to bet bad weather doesn't affect incorporeal flying undead very much ...
Fourth, the Bouncing Spell metamagic feat might be useful. With this feat, if the first target makes its saving throw or what have you, then the spell bounces to another PC target. That might be fun for your players.
Fifth ... are you using the Mythic rules? If so, you can throw a LOT of epic-level craziness at your players. Here's one: Take the top baddy to mythic tier 8. Have him cast the augmented/mythic version of Sands of Time on the PCs.
Sixth, don't be afraid to take away some of their toys. An opponent armed with a Pilfering Hand and/or Improved/Greater Disarm, Steal, or Sunder can make things difficult for them.
As I think about it, a little bit of misdirection REALLY makes sense here. Do your players have a good idea what the Big Bad looks like? That's great. Make the big chief of this encounter look at lot like the Big Bad, but have him use scrolls, wondrous items, staves, and other magic items to accomplish his effects. Also, if you use music when playing your game, play something like the Beowulf theme when this guy appears. Do everything you can to encourage your players to believe this guy has the major mojo. Then, once that guy's dead .... introduce the REAL BBEG. And cue up O Fortuna on your campaign soundtrack.
I agree with pennywit on the troop and swarm idea, rolling 27 or more dices per round means it's going to take a while. Even if the fight is over on round 3. On the subject of shadows, however, I think they still need a leader. Just statted up this thing, it might work..
*cracks knuckles*
Shadow Queen:
Roiling umbral mass of heads and tentacles erupts from the rock, atop of which a distorted, shadowy form of a woman can be seen
Dread Shadow Scylla CR 18
XP 153,600
CE Huge Undead (Augmented Aberration, Incorporeal)
Init +11; Senses all-around vision, blindsight 30 ft., darkvision 60 ft., low-light vision, see invisibility; Perception +30
Aura frightful presence (30 ft., DC 28)
DEFENSE
AC 30, touch 20, flat-footed 18 (+13 dex, +8 deflection, +1 dodge, , –2 size)
hp 250 (20d8+160); fast healing 10
Fort +14, Ref +19, Will +11
Defensive Abilities Channel Resistance +3, freedom of movement, improved evasion, Incorporeal;
DR 10/cold iron and lawful; Immune cold, charm effects, confusion and insanity effects, undead traits; Resist acid 20, fire 20; SR 29
OFFENSE
Speed Fly 50 ft. (Perfect)
Melee incorporeal 4 bites +27 (1d8 Str/19–20), 4 tentacles +25 (1d8 Str)
Space 15 ft.; Reach 15 ft.
Special Attacks Strength damage
Spell-Like Abilities (CL 16th; concentration +26)
Constant—freedom of movement, nondetection, see invisibility
At will—acid arrow, control water, fog cloud, Greater dispel magic, major image (DC 21), shadow slip
3/day—black tentacles, charm monster (DC 22), insanity (DC 25), mirage arcana (DC 23), solid fog
1/day—control weather, power word stun, project image (DC 25), summon (level 8, 1 charybdis)
STATISTICS
Str -, Dex 36, Con -, Int 16, Wis 25, Cha 26
Base Atk +15; CMB - CMD -
Feats Combat Reflexes (14 AoOs), Dimensional Agility, Dimensional Assault, Dodge, Improved Critical (bite), Mobility, Multiattack, Weapon Finesse, Weapon Focus (bite), Weapon Focus (tentacles)
Skills Bluff +28, Fly +41, Intimidate +31, Perception +30, Sense Motive +26, Stealth +28 (+32 in dim light, +24 in bright light), Use Magic Device +26
Languages Abyssal, Aquan, Common
SQ amphibious, change shape (1 humanoid form, alter self), undersized weapons*
Command Shadows (Su):
As a free action, a dread
shadow can automatically command all normal
shadows within 30 feet (as command undead).
Normal shadows never attack a dread shadow unless
compelled
Create Spawn (Su):
Any creature with a Charisma
score of 15 or higher that is killed by a dread shadow
rises as a dread shadow in 1d4 rounds. Any other
creature slain by a dread shadow instead rises as a
normal shadow. A shadow or dread shadow created
in this manner is under the command of its creator
(as dominate monster) and remains so until either it or
the creator is destroyed.
Shadow Slip (Su):
At will, a dread shadow can use
dimension door as the spell (caster level 7th) as a
move action. It must move from a place of darkness
or shadow to another place or darkness or shadow
within line of sight. Using this ability does not
provoke an attack of opportunity.
Strength Damage (Su):
A creature struck by a dread
shadow’s incorporeal touch attack takes Strength
damage depending on its size: Fine-Tiny: 1d4 Str,
Small-Large: 1d6 Str, Huge-Colossal: 1d8 Str.
This is a negative energy effect. A creature dies if
this Strength damage equals or exceeds its actual
Strength score.
That should be little more difficult to damage, and it certainly cannot be dazed. Dispel or Disjunction the inevitable Death Ward and pound that wizard into a shadow. If it gets hit too badly it will just slip into a rock to heal. This thing might also make somewhat convincing "Faux Ultimate Villain", as Pennywit suggested.
* As Rerednaw did so, I too should point out that both the swarm and this thing use templates from Green Ronin's Advanced Bestiary (PFRPG edition), Paizo's go-to book for templates. If you want to keep things 100% Raw, then I'm probably not of that much help..
Already using a lot of deception. Both players and PCs believe they know what's going on ... One minion will certainly look like the BBEG, whom they have seen. This minion may provide a great distraction, but is very unlikely to survive round 1 ...
Bouncing metamagic will be in use. Save-or-suck spells will still almost always fail, because save-on-a-2 combined with rerolls.
This is obviously not PFS, and I'm not worried about RAW. I do want to keep anything especially nasty and lethal in the realm of RAW, in case the PCs lose. A GM can always invent stuff that makes the PCs lose, but doing so in a mostly-RAW way will surely be more satisfying to the players.
I'll certainly use troops and swarm mechanics, to simplify book keeping.
I like the Shadow Queen, and will use her flavor for the Shadow Boss.
If you go round one polar midnight throw things immune to cold like autumn death, have each begin with enervate to reduce their saves (in general spam enervate to reduce saves), winterwights can polar ray then spam greater dispel and sleet storm to reduce visibility, Nightwalkers can tank and get swift sunder attempts each round, they can buff prefight with haste and invis and quicken unholys blight 3/day.
Fill the lair with Nightmare Vapor, the undead will be immune, the party will almost certainly make the save (until they take enough enervates) but even one fail can be devastating and they will need to save each round.
layer defenses for spell casters in the back ie project image and/or mirror image, cast then move into areas of concealment (deeper darkness, solid fog, sleet storm), after that they can move, cast then have other enemies throw down more concealment, if they are also undead find a way to give them lifesense or ability to see in deeper darkness (rod of shadows). Hand rods out like candy, give someone a rod a negation, target primary weapons, a cloak of resist or whatever magical crutch they depend on most.
Orrrr ... At the end of the combat, pink fog fills the area, and a great mirrored sphere descends from the heavens. A lich, dressed in an immaculate white shirt and pants, moves toward the party, making arcane, suggestive gestures.
He chants a fearsome spell:
A Most Frightening Magic:
Well, you can tell by the way I use my walk,
I'm a woman's man: no time to talk.
Music loud and women warm, I've been kicked around
Since I was born.
And now it's all right. It's OK.
And you may look the other way.
We can try to understand
The New York Times' effect on man.
Whether you're a brother or whether you're a mother,
You're stayin' alive, stayin' alive.
Feel the city breakin' and everybody shakin',
And we're stayin' alive, stayin' alive.
Ah, ha, ha, ha, stayin' alive, stayin' alive.
Ah, ha, ha, ha, stayin' alive.
This fearsome creature may be defeated .... only in a dance battle.
Did ANY of your super-duper-uber optimized players take ranks in Perform (dance)?
In the alternative, perhaps they can win the combat only by beating Norgorber in a Craft (basketry) skill challenge.
Also throw down Silence on their teleport spot and continue to pepper silence throughout the area, most undead won't need sound. If anyone has less then 200 hp use Powerword Blind.
Maze(level 8) is also no save, target whoever has the lowest int score.
Wave of Ecstasy will at least stagger them, preventing full round attack actions.
Use walls of stone to split the party, try to remove line of effect from healers, all the incorporeal undead can just fly right through them. Give a belt of shadowform to a spellcaster who needs to be incorporeal.
Note that all the PCs have excellent layered defenses. In particular, the Wizard has gone to great effort to keep most of them protected with Mind Blank. So most mind-affecting things are right out.
mind blank is very good but only grants a bonus to saves not immunity. Lifesense will overcome mind blank as well even if they are also invisible. Also mind blank will likely be one of the first things lost to greater dispels, what caster level are you rolling against?
If targeting them is difficult then use glitterdust. Since they will be unable to teleport forcecage becomes very effective to trap players, since reflex negates use only after you reduce their dex to have a chance.
I assume the diviner has freedom of movement, if you can remove it then start a grapple action, hollow serpent can keep a spell caster grappled, it is also a source for wave of exhaustion.
Have an illusion of your BBEG standing in the middle of a Teleport circle trap(s) to an area made with Create Greater demi-plane. He taunts them with "HAHAHA fools, now I have drained your power and am a Demi-gawd! Run the pcs around until they all get teleported. Create a Demiplane negative/dead magic with a locked gateway to the negative plane that is connected to a river/pool/ocean of unholy/acid/undead oozes, and then fill the rest of the room with 250000 undead shadow swarm flying ghost hamsters. Each hamster has a tiny necklace with a tiny key, but only One of the 250000 that unlocks the gate, and they are made of something melty that the acid pools eat.
You could vary the magic level to give them a chance. Make them play on your ground, not theirs.
i don't know if you have the same stuff at pathfinder (my dm asked me not to look at dm matirial as the monster manual and mgical item parts) BUT in D&D 3.5 a fellow dm asked me to help her plan a very nasty counter attack that a vempire would do to the group. she had a high level group with very effective casters and melee's. after she took what i had offered she actuly had to lower it down a bitto give them a chacne.
so here goes. this is an inner room right after the base guards outsides (who once defeated scream :" the ELITE's will finish you off. you are doomed" etc etc.
it starts as a long corador .floor and ciling is wooden interlocing beams with gaps betwin them (think of a basket patren with holes the size of 10 CM radius. big enough to snag a leg. but not fall over, if your not carful.
the walls have draps on both sides that moves wit hthe winds but actuly hide nothing behind it.(real danger is from bellow and above)
as the aprty move along (hopefully if the corador is long enough they will also seperate somewhat) the ambush is sprung. the attackers are vampire spawns sprites (or what ever fey had the improved invisible constat ability). they launch the 1st attac kfrom above : itching and coughing poweder. in ase you don't remmeber in 3.5 this will stune and or kill even wih a save. the best part is even if they save, they drop what eer they are holding (most likely their best weapons). which will go to the floor bellow. that hosta hordeof rust monsters...
2nd part of attack(asuming the cleric got hit and didnt turn the undead to mince) is each two get VERY close to each party member and use a bid of force(trapping all 3 in a force sphere) where they will go into grapple mode sucking up their target's levels and making usre that eac hcharacter can't help an other.
i actuly got angery phone calls from that gm's players once they learned i gave her that idae ;)
I ran another grind session tonight, wearing them down. One PC, the Bloodrager, went down and nearly died, and all took substantial damage. After slaying many foes, but not more than 1/4 what was on the field of battle, they decided to flee. They were wounded about 25% (after several heal spells), bloody, tired, exhausted, more than 50% depleted of resources, when they decided to teleport back to safety ... and into the horrible prepared ambush.
We left things at the start of the combat round on which they teleported in, after a description of the ambush scene. We'll gleefully take up the probable TPK in two weeks. I give them 40% chance of surviving as a team, an 80% chance at least one PC surviving, and a 20% chance they still manage to take down Karzoug.
I do have a question, how are they saving on a 2 with a re-roll? If they are I would use spells that mess them up even if they do save. And in any case you've already taken out the big guns with Disjunction if any of the PC's save bonuses are from items...they are going to lose a lot of them after that nuke goes off.
And with Limited Wish you can give the players a -7 on their next save (saving throw: none). Stacked with Persistent metamagic(roll twice take worse) and some spells will land.
If they party has fire resistance (saw the burning skeleton idea) then swap them out for frost skeletons (same but auto cold damage and explode for cold when destroyed).
Also stack up on defensive spells that do damage when you are hit (defensive shock, fire shield).
A caster neutralizer (on top of silence, anti-magic shell and disjunction) is Call the Void. Auto-damage cannot speak or breathe while adjacent even if they make their save. Though grappling critters or swarms work as well.
And since I think this has gotten to the silly point: Explosive Runes every single disposable grunt has that on stuck on paper's glued to their shield, breastplate, etc. Have these all over the floors, walls, and ceiling when the party teleports in. Anyone who reads them takes damage, no save. Within 10 feet take damage (but can save for 1/2). The party can then decide to not read by closing their eyes and now you have total concealment against them.
Be sure to time the Disjunction for right after all the instant magic damage effects and magic traps go off.
EDIT: Oh yeah, forgot...since we are bringing in everything. Don't forget the joys of Blasphemy/Holy Word, especially when you use tricks to jack up the caster level. (Prayer Bead, Iuon Stone, Traits, Archetypes, Feats, Domains-pretty easy to get an effective +10 to your CL). So given your bad guys, that is around CL 24.
Not knowing what your party level is:
PRD wrote:
Equal to caster level Deafened
Up to caster level -1 Blinded, deafened
Up to caster level -5 Paralyzed, blinded, deafened
Up to caster level -10 Killed, paralyzed, blinded, deafened
The effects are cumulative and concurrent. A successful Will save reduces or eliminates these effects. Creatures affected by multiple effects make only one save and apply the result to all the effects.
Deafened: The creature is deafened for 1d4 rounds. Save negates.
Blinded: The creature is blinded for 2d4 rounds. Save reduces the blinded effect to 1d4 rounds.
Paralyzed: The creature is paralyzed and helpless for 1d10 minutes. Save reduces the paralyzed effect to 1 round.
Killed: Living creatures die. Undead creatures are destroyed. Save negates. If the save is successful, the creature instead takes 3d6 points of damage + 1 point per caster level (maximum +25).
So assuming that after all their magic items and defenses are stripped, and that the PC's are level 19 or less even if they make all their saves they are still Blinded and Paralyzed. Time for Coup de Graces at that point.
Oh with regards to my Planar Ally/Binding: Glabrezu Demons (Wishes for everyone!) and Reverse Gravity and Power Word, Stun Or Planetars for their spells, or any of the various Angels really.
Summon some Cyclops as well. After the party is paralyzed, they are d-doored in (or summoned adjacent) by another and crit the helpless PC's. That's an average of 54 damage or DC 64* Fort save or die. If necessary, the Cyclops could use Flash of Insight for another auto-threat/crit.
*If after all this your PC's still save on a 2, then I'm thinking there's something a wee bit off here. :)
Teleport Trap and Clone could make this ambush a whole lot messier and more interesting at the same time, though it requires the bad guys to have previous experience with the heroes. The short version... separate the party effortlessly by making some of them exempt from the Teleport Trap (most of the rest will be left behind when they make their presumably easy Will Saves). Kill the fraction of the party that arrives in any of the ways described above. Have Clone spells prepared to get around a wide array of contingency plans. The slain are shunted into bodies that are already in restraints or worse (being reanimated in a body lacking hands or a tongue would be quite the hardship for spellcasters). The fraction that made their initial save? Well, now they know there's a trap waiting for them, but they have little choice but to go in at reduced strength to rescue their friends.
I suggest this route because your goal still seems to be to make things challenging and interesting, not simply to slaughter them. This approach forces a revision in tactics, steals momentum from the party, uses their own strengths against them and is very specifically not a TPK.
Incidentally, if you do just want death... I think you're fixating a bit too much on the exotic. You noted that you have enough shadows to statistically guarantee attribute attrition. Fine. But you also have 500 skeletons and no reason at all they shouldn't be filling the skies with arrows each turn (the shadows won't mind). 500 bows should land 25 hits a turn no matter how good their defenses are. Unless everyone in the party also has lots of damage reduction or vast wells of healing (which I kind of figured they might have tapped if they're retreating to this location), that will add up fast with minimal effort on the part of the BBEG.
I ran another grind session tonight, wearing them down. One PC, the Bloodrager, went down and nearly died, and all took substantial damage. After slaying many foes, but not more than 1/4 what was on the field of battle, they decided to flee. They were wounded about 25% (after several heal spells), bloody, tired, exhausted, more than 50% depleted of resources, when they decided to teleport back to safety ... and into the horrible prepared ambush.
We left things at the start of the combat round on which they teleported in, after a description of the ambush scene. We'll gleefully take up the probable TPK in two weeks. I give them 40% chance of surviving as a team, an 80% chance at least one PC surviving, and a 20% chance they still manage to take down Karzoug.
Another +1, that was my next piece of advice: layering encounters. The trick with an ambush is to lay it to hit a reactive party or NPC group. You don't want to hit them when they're full and traveling, you want to hit them when they are weak and fleeing.
Keep in mind that it's important to be fair with mass minion mechanics. I always try to stay consistent when I'm moving hordes of baddies around the heros by moving all first then attack all next, so that players can ready reasonably. Vastly imbalanced action economies can lead to victories purely by exploiting move/attack mechanics, which is no fun.
