Atropal?

[PraxisVetli]

My players are on their way to got fight the BBEG in the area they're in.
But I would like to spiffen it up a bit, maybe add some class levels.
But it looks poorly designed. Its biggest strategy seems to be slight de-buffing while its commanded mooks murder the party.
But I didn't really want to have a mookfest for this encounter, are there other ways this creature could go?

[Chronikoce]

Are you referring to the CR 30 Atropal that can be viewed on the 3.5 SRD site? Because in that case I would not consider 2d6 Con drain and a ray attack that delivers 4 negative levels to be a slight debuff.

It also has a full compliment of high level spellcasting abilities which can be used to annihilate your party. Greater Invisibility+Eye Ray Attacks/Blasphemy/Finger of Death/Weird. It also has high Int and Wis so it should be intelligent enough to use any mooks it does possess to apply buffs to itself for protection and even more effective destroying.

It definitely isn't the most terrifying creature that you could throw at a party but Weird has a cast range beyond true seeing and see invisibility so your party could be significantly weakened before they even identify the location of the threat.

--Edit--
I actually avoid creatures like the Atropal as enemies because the abilities that are powerful tend to result in save or suck. If Atropal casts weird while invisible and the player's have some bad rolls then the BBEG fight just turned into a round or two of players dropping dead. You may have a different style of DM'ing than I do though which could lead to this being a perfectly fine or even underpowered encounter.

[PraxisVetli]

Are you referring to the CR 30 Atropal that can be viewed on the 3.5 SRD site? Because in that case I would not consider 2d6 Con drain and a ray attack that delivers 4 negative levels to be a slight debuff.

It also has a full compliment of high level spellcasting abilities which can be used to annihilate your party. Greater Invisibility+Eye Ray Attacks/Blasphemy/Finger of Death/Weird. It also has high Int and Wis so it should be intelligent enough to use any mooks it does possess to apply buffs to itself for protection and even more effective destroying.

It definitely isn't the most terrifying creature that you could throw at a party but Weird has a cast range beyond true seeing and see invisibility so your party could be significantly weakened before they even identify the location of the threat.

Aye, thats the one.
Weird seems meh, with the dual save.
The eye ray would be more impressive if that 400' range didn't need LoS.
The party's evil, so Blasphemy is negated.
So Finger of Death.
Fort vs death stopped being scary a long time ago.
And the max 43 dmg is something they won't even notice...
Counter Edit!
The saves aren't that intimidating for them, and yeah, they're pretty capable.
I gotta beef this thing up or it'll die first round. Three of the four will pool resources to enable the fourth to obliterate. The Atropal as listed won't survive a full attack from any one of them.

[Bluydee]

I once did this before, but what I did was enlarge the Atropal to the size of a moon, and reveal the BBEG is simply a bunch of cultists heralding the Atropal as it came closer and closer before crashing into the material plane. I then just made the encounter of a race against time to try and activate the macguffin earlier to gate it into the sun.

[PraxisVetli]

I once did this before, but what I did was enlarge the Atropal to the size of a moon, and reveal the BBEG is simply a bunch of cultists heralding the Atropal as it came closer and closer before crashing into the material plane. I then just made the encounter of a race against time to try and activate the macguffin earlier to gate it into the sun.

You Atropus'd your Atropal?
Yo dawg.
this is certainly cool, except there isnt time for a new quest. The campaign arch is ending, and they know it.

[sleepyphoenixx]

The question is why you'd want to use a monster that's clearly geared for minionmancy in any other capacity instead of just switching it for something that fits with what you have in mind.

As it is the Atropal by itself isn't a serious threat even to a ECL 20 party as long as they have level appropiate protections.

[Melcar]

Aye, thats the one.
Weird seems meh, with the dual save.
The eye ray would be more impressive if that 400' range didn't need LoS.
The party's evil, so Blasphemy is negated.
So Finger of Death.
Fort vs death stopped being scary a long time ago.
And the max 43 dmg is something they won't even notice...
Counter Edit!
The saves aren't that intimidating for them, and yeah, they're pretty capable.
I gotta beef this thing up or it'll die first round. Three of the four will pool resources to enable the fourth to obliterate. The Atropal as listed won't survive a full attack from any one of them.

Two comments.

1) Give it the Paragon (http://www.d20srd.org/srd/epic/monsters/paragonCreature.htm) template, that should take care of everything...

2) If it dies in the first round, you are playing in wrong!

[PraxisVetli]

The question is why you'd want to use a monster that's clearly geared for minionmancy in any other capacity instead of just switching it for something that fits with what you have in mind.

As it is the Atropal by itself isn't a serious threat even to a ECL 20 party as long as they have level appropiate protections.
Because I foolishly hinted that's what they are against before realizing I dun goofed.
Now I gotta deal with it lol.

Two comments.

1) Give it the Paragon (http://www.d20srd.org/srd/epic/monsters/paragonCreature.htm) template, that should take care of everything...

2) If it dies in the first round, you are playing in wrong!

1. Aye, Paragon's a thing I'm very familiar with. But that's definitely a CR to big, and the Atropal wouldn't get all that much better from Paragon. Bigger numbers, aye, but I need Better numbers.
2. Well, what would you suggest?
How should I play it?

[daremetoidareyo]

Aye, thats the one.
Weird seems meh, with the dual save.
The eye ray would be more impressive if that 400' range didn't need LoS.


Ahhhh, but the greater invisibled projected image of atropus has a 400'range, and can use things off of his spell list, like weird. And atropus knows how to use a spyglass and can therefor be 790' away.

Give him tactics. A smart atropus is a scary atropus. He can plane shift at will. Greater invisibility, spectral hand, teleport behind the party, then plane shift the biggest buffest guy to the paraelemental plane of magma while they're flat footed, while the spectral hand delivers a quickened slay living on an obvious caster (3d6+30 on a failed fort save DC 31) Then energy drain a different caster with the eye ray and plane shift to a border region of the negative energy plane to heal and then repeat.

Throughout the day, you'll tax those casters real hard, (hopefully they'll rig some wizard eyes, true seeing and contingencies) and they'll be hurting by the time they have the big face-off. Just getting their meat shield back will take some time, probably a limited wish. Fighting atropus should happen in 3 or 4 bursts unless the PCs figure out how to turn the tables of an enemy that can invisibly teleport himself and doubles of himself into and around the party, on top of an army of devourers and specters he creates out of corpses that he finds.

And don't forget that PC are treated as having 10 levels energy drained while in his presence without negative energy protection, which atropal is sure to send some devourers and specters to sunder or steal.

[Chronikoce]

Aye, thats the one.
The saves aren't that intimidating for them, and yeah, they're pretty capable.
I gotta beef this thing up or it'll die first round. Three of the four will pool resources to enable the fourth to obliterate. The Atropal as listed won't survive a full attack from any one of them.

You could go for a really rather strange strategy. The Atropal gets the spell-like ability plane shift. They also can summon 5 nightcrawlers per day. Running under the assumption that the nightcrawler obeys the Atropal and can be considered a willing subject the following shenigans becomes possible.

Summon 5 nightcrawlers, have them all attack the party from under the ground at one time. Atropal is invisible and flying close enough to witness the engagement. If any of the nightcrawlers manage to land an attack they then proceed to swallow a party member using swallow whole. Once a party member is swallowed the Atropal flies in and plane shifts the nightcrawler away (willing subject no save). If you send the nightcrawler to the negative energy plane then I presume they will be having a pretty bad day at that point.

This plan operates under a major assumption that every party member cannot plane shift. If every party member has access to planar travel through magic or items then this attack would fail.

[Melcar]

Because I foolishly hinted that's what they are against before realizing I dun goofed.
Now I gotta deal with it lol.


1. Aye, Paragon's a thing I'm very familiar with. But that's definitely a CR to big, and the Atropal wouldn't get all that much better from Paragon. Bigger numbers, aye, but I need Better numbers.
2. Well, what would you suggest?
How should I play it?

First of all... What classes are there in the party?

Secondly... make good use of the fly speed has, and remember to devastating critical feat it has. It has damage reduction, fast healing, high SP. Unless the party is filled with tier 1s I would say that with 240 fly speed, it should be out of reach from any melee. And as far as I recall Death Ward does not stop con drain.

[daremetoidareyo]

You could go for a really rather strange strategy. The Atropal gets the spell-like ability plane shift. They also can summon 5 nightcrawlers per day. Running under the assumption that the nightcrawler obeys the Atropal and can be considered a willing subject the following shenigans becomes possible.

Summon 5 nightcrawlers, have them all attack the party from under the ground at one time. Atropal is invisible and flying close enough to witness the engagement. If any of the nightcrawlers manage to land an attack they then proceed to swallow a party member using swallow whole. Once a party member is swallowed the Atropal flies in and plane shifts the nightcrawler away (willing subject no save). If you send the nightcrawler to the negative energy plane then I presume they will be having a pretty bad day at that point.

This plan operates under a major assumption that every party member cannot plane shift. If every party member has access to planar travel through magic or items then this attack would fail.

Atropus doesn't even need to be there, the night crawlers get plane shift by themselves. Atropus can greater teleport them underneath the party, they night crawlers ambush, those that swallow whole on round one, do a quickened plane shift on round 2, assuming the PCs have negative energy protection, the night crawlers don't need to breath, so plane shifting to the elemental plane of water is a good choice. They break free and then begin the drowning rules in a lightless gravityless miasma of water.

[PraxisVetli]

First of all... What classes are there in the party?

Secondly... make good use of the fly speed has, and remember to devastating critical feat it has. It has damage reduction, fast healing, high SP. Unless the party is filled with tier 1s I would say that with 240 fly speed, it should be out of reach from any melee. And as far as I recall Death Ward does not stop con drain.

Classes are...
hold on to your butts..
a rogue/lasher swordsage (lotta setting sun and trip lockdown
Stalker ranger (Solar Wind)
Monk Warblade jet with ~11 atks/round. Capable of 2-3 full attacks. avg 1.5-2k dmg output/round.
Draegloth Duskblade. Similiar output.
and group cohort Warmage/Rainbow Servant. used primarily as heals, though certainly capable of more, though I wouldn't bank on it.
IMPORTANT.
The group is CAPABLE. they have flight, they have Freedom of Movement, they each have the list of Neccesary Magic Items.
Also. plan would work well, except FoM and while teleporting is fine, they're, to shorten a long story, in a demi-plane that doesn't allow planar travel.

[Chronikoce]

I didn't read the nightcrawler thoroughly enough. Since they can plane shift themselves that is even better.

Looking at party make-up it seems like any party members you manage to shift to another plane are going to be out of commission unless they have an item to assist them. Depending on their defenses and the level of knowledge the Atropal has about the party it could be intelligent enough to pick the appropriate plane. Water to drown, negative energy to kill (assuming no immunity), Fire to burn, etc.

--Edit--
My apologies, I didn't notice the Demi-Plane prevents planar travel.

[sleepyphoenixx]

You're forgetting that the Atropal is up against an epic level party. Unless they're remarkably unprepared things like Death Ward/Soulfire, Mind Blank, Sheltered Vitality, Freedom of Movement and various ways to avoid being surprised and/or flat footed have been standard for several levels, even for noncasters.
Sure, it has Greater Dispel at will but that doesn't do anything against buffs with a CL of 25 or more, assuming nobody has a Ring of Counterspells or other dispel protection (which should also be standard at that level).

I can buy that the party doesn't have all of those at lower levels. At epic though everyone has enough WBL to cover those several times over and it sounds like the OPs party is on the competent side, so pretty much all of the Atropals abilities are negated by equipment or the parties standard daily buffing routine.

That leaves a few underwhelming summons and undead-boosting abilities the OP doesn't want to use, a pile of HP and an okay chance to escape. It can't even damage a party with the proper protections. Not exactly an epic encounter.

Unless you've told the party what they're facing by name and can't weasel around it somehow i'd definitely replace it with something else. Turning that thing into a proper challenge is pretty much impossible without resorting to minions imo.

[PraxisVetli]

you're forgetting that the atropal is up against an epic level party. Unless they're remarkably unprepared things like death ward/soulfire, mind blank, sheltered vitality, freedom of movement and various ways to avoid being surprised and/or flat footed have been standard for several levels, even for noncasters.
Sure, it has greater dispel at will but that doesn't do anything against buffs with a cl of 25 or more, assuming nobody has a ring of counterspells or other dispel protection (which should also be standard at that level).

I can buy that the party doesn't have all of those at lower levels. At epic though everyone has enough wbl to cover those several times over and it sounds like the ops party is on the competent side, so pretty much all of the atropals abilities are negated by equipment or the parties standard daily buffing routine.

That leaves a few underwhelming summons and undead-boosting abilities the op doesn't want to use, a pile of hp and an okay chance to escape. It can't even damage a party with the proper protections. Not exactly an epic encounter.

Unless you've told the party what they're facing by name and can't weasel around it somehow i'd definitely replace it with something else. Turning that thing into a proper challenge is pretty much impossible without resorting to minions imo.

this is an exact description of my dilemna.


NEW PLAN.
Is there anything that I can make resemble an atropal that wont get fistfed butthurt?

[Chronikoce]

I have to agree with Sleepypheonix.

Unfortunately the situation you have described appears stacked against the Atropal pretty heavily. It relies on not being engaged directly for its assaults. By removing the planar travel option and not wanting to throw minions at the group I don't see an option for the Atropal to win as written.

Simplest option: Swap the enemy out for something that arguably could fit the description you gave (unless they know it by name).

Option 2: Advance the Atropal with class levels. Provide the appropriate casting level needed to present a threat to the party through spells it gains.

Option 3: Apply templates to it which grant new terrifying abilities or defenses which can deal with the parties damage output.

The only other way I can think of is the option that daremetoidareyo already gave. Harass the party all day long through use of Project image and only attack once they are reduced to a non-threatening status. That doesn't sound like the sort of climactic combat you are looking for though.

[daremetoidareyo]

It sounds then you need to make this atropal a super sophisticated illusion made by a way more badA villain to distract the PCs then.

Might I suggest fighting said villain in an anti magic zone, with his skills ripped right from that monk war blade, only 3 category sizes larger with d20s for hp, and an extraordinary ability to haste himself and timestop. Now entering: The cosmic heavy weight champion of the material planes. Also, this guy is just a dude who some bigger badder dude convinced to fight with the PCs incase they saw through his complicated atropal illusion....

[Melcar]

Classes are...
hold on to your butts..
a rogue/lasher swordsage (lotta setting sun and trip lockdown
Stalker ranger (Solar Wind)
Monk Warblade jet with ~11 atks/round. Capable of 2-3 full attacks. avg 1.5-2k dmg output/round.
Draegloth Duskblade. Similiar output.
and group cohort Warmage/Rainbow Servant. used primarily as heals, though certainly capable of more, though I wouldn't bank on it.
IMPORTANT.
The group is CAPABLE. they have flight, they have Freedom of Movement, they each have the list of Neccesary Magic Items.
Also. plan would work well, except FoM and while teleporting is fine, they're, to shorten a long story, in a demi-plane that doesn't allow planar travel.

Could you disclose their level? ANyways thats seems pretty hardcore. Not quite sure how a monk does that but, i either case... go paragon. You say that would be to much, but if two of the party can do around 1k damage a round, I would say do it. If thats not enough do what I always do, when wanting to seriusly beat the living/undead poo out of my players. The ancient red wyrm, draco demi-lich. I usually just give it the minimum 21CL, thats usuially 21 too much anyways, but if not, give it 12 levels of dragon ascendant.

I said you were playing wrong, but with that sort of party power I'm not sure what to do... it seems well too much even for me...:smallamused:

EDIT: Come to think of it, why not just turn the Atropal into a demi lich?

[Silva Stormrage]

this is an exact description of my dilemna.


NEW PLAN.
Is there anything that I can make resemble an atropal that wont get fistfed butthurt?

Give it divine rank 1 and access to the alter reality salient divine ability. Then stack all the buffs on the game on itself and hit the party with multiple disjunctions and use the hit and run tactics suggested above.

Pro's: Makes the atropal actually terrifying to fight as it can throw off ANY spell 9th level or lower.

Con's: Basically they are fighting a caster and the fight lose's some of its feel.

[Melcar]

Con's: Basically they are fighting a caster and the fight lose's some of its feel.

Indeed... the easy thing might simply be to advance it some HD

[PraxisVetli]

Indeed... the easy thing might simply be to advance it some HD


Give it divine rank 1 and access to the alter reality salient divine ability. Then stack all the buffs on the game on itself and hit the party with multiple disjunctions and use the hit and run tactics suggested above.

Pro's: Makes the atropal actually terrifying to fight as it can throw off ANY spell 9th level or lower.

Con's: Basically they are fighting a caster and the fight lose's some of its feel.


Could you disclose their level? ANyways thats seems pretty hardcore. Not quite sure how a monk does that but, i either case... go paragon. You say that would be to much, but if two of the party can do around 1k damage a round, I would say do it. If thats not enough do what I always do, when wanting to seriusly beat the living/undead poo out of my players. The ancient red wyrm, draco demi-lich. I usually just give it the minimum 21CL, thats usuially 21 too much anyways, but if not, give it 12 levels of dragon ascendant.

I said you were playing wrong, but with that sort of party power I'm not sure what to do... it seems well too much even for me...:smallamused:

EDIT: Come to think of it, why not just turn the Atropal into a demi lich?


I have to agree with Sleepypheonix.

Unfortunately the situation you have described appears stacked against the Atropal pretty heavily. It relies on not being engaged directly for its assaults. By removing the planar travel option and not wanting to throw minions at the group I don't see an option for the Atropal to win as written.

Simplest option: Swap the enemy out for something that arguably could fit the description you gave (unless they know it by name).

Option 2: Advance the Atropal with class levels. Provide the appropriate casting level needed to present a threat to the party through spells it gains.

Option 3: Apply templates to it which grant new terrifying abilities or defenses which can deal with the parties damage output.

The only other way I can think of is the option that daremetoidareyo already gave. Harass the party all day long through use of Project image and only attack once they are reduced to a non-threatening status. That doesn't sound like the sort of climactic combat you are looking for though.

The party is roughly 33-34. Which is why I'm trying to spice it up.
In no particular order..
What kind of class levels do you give something like this? Or templates? While Paragon and Demi Lich are great, Demi Lich is too much, and Paragon is really just going to add higher DC's to effects that don't even matter, and extra HP. and While HP is great, I worry that'll make it more annoying, not dramatic.
I'm not opposed to changing the boss, though I've about an hour to crap one out. While the Atropal has been described, the words haven't been said. So I can switch if necessary.

I want to put out that the Nightcrawler/teleport/planeshift plan is nothing short of excellent, and totally would use if could.

I think I want to switch it out. but what else can fit the idea of, to quote a player "Giant undead space baby"?

[Phelix-Mu]

I like Silva's idea, frankly. But if you want to keep some of the atropal flavor:

Atropal, Fragment of Unmaking:

Since it's got all that NEP stuff anyway, why not jazz it up a bit? Voidstones are the ultimate manifestations of negative energy and cause disintegration effects on contact.

So homebrew up some extreme effects, place a couple voidstones around the atropal.

Effect 1: The voidstones disintegrate matter on contact. This includes air. A powerful vortex surrounds the atropal, drawing in the surrounding terrain. Fluff this as The Nothing from The Neverending Story to impress people of a certain age group and provide imagery. You can probably YouTube the scenes from that movie for narrative inspiration. Fluff-wise, I'd probably make it hurricane-strength. It deafens everyone in the radius, and even if they are protected from deafness, they still can't hear over the infernal din. Everything gets non-magical concealment, as dust, debris, trees, and everything is sucked toward the center of the vortex.

Not extreme enough? Make several vortices. As the characters enter areas of overlap near the atropal, opposing forces tear at them, doing non-magical damage and randomly bull-rushing them around with a high modifier (base it on the atropal's high stat). Ranged touch spells and other missiles likewise are affected, being thrown wildly off-course and affected as the atropal consumes even the magical energies that power spells.

Not extreme enough? The voidstones are sentient and have Su abilities equivalent to psion 20s, the amalgamated psychic detritus of all they have consumed. Proceed to deliver a beating worthy of the Tippyverse.

Effect 2: The voidstones consume air, meaning the area near the atropal (pick a round number, 30' or 60' are common) is airless and void, which I think the game establishes somewhere as dealing continuous cold damage.

Effect 3: The fabric of time itself breaks down near the atropal. Every few rounds (pick a number), the atropal gets a free non-magical, maximized time stop, essentially 5 free rounds of healing and self-buffing. To the characters, it literally looks like the thing teleports around, magically recovers, and otherwise can reestablish its defensive and prep new assaults.

The key to winning is to maneuver the atropal away from the more deadly area near the voidstones, trying to flush it out of its area.

This has more boss-fight flavor, is thematically undead without the minionmancy, and suitably epic visuals. It also makes the thing a bonafide threat to way more than just mortals, as it could conceivably wreck the entire Prime (or anywhere else) if it wanted to and was unopposed.

EDIT: In light of the level of the characters, toss all the Entropomancer abilities on the atropal as Ex, DCs set to its racial abilities, and maybe have it go around with some umbral blots in tow (easier than scaling up a sphere of annihilation to be an epic threat). I'd go evolved undead template before the other stuff, apply multiple times to taste.

[Melcar]

The party is roughly 33-34. Which is why I'm trying to spice it up.
In no particular order..
What kind of class levels do you give something like this? Or templates? While Paragon and Demi Lich are great, Demi Lich is too much, and Paragon is really just going to add higher DC's to effects that don't even matter, and extra HP. and While HP is great, I worry that'll make it more annoying, not dramatic.
I'm not opposed to changing the boss, though I've about an hour to crap one out. While the Atropal has been described, the words haven't been said. So I can switch if necessary.

I want to put out that the Nightcrawler/teleport/planeshift plan is nothing short of excellent, and totally would use if could.

I think I want to switch it out. but what else can fit the idea of, to quote a player "Giant undead space baby"?

What do you want the atropal to be able to do? More of what it already has, or a lot of interesting abilities?

EDIT: WHat about the pseudonatural template? Or perhaps the Elder Brain lich?

[The Insaniac]

Another option, if it doesn't need to be an atropal, is to run an advanced phane. IIRC, phanes are just about the only abominations actually worth their CR.

Edit: Just remembered you said they were evil. Do they normally have protection from evil up? If not, they're in for a really nasty surprise from an atropal.

[ranagrande]

Do you by any chance have access to the Munchkin d20 Monster manual? A Wyrmling Plutonium Dragon Dracolich would fit the profile of "giant undead baby" and provide an interesting challenge for your party.

[PraxisVetli]

I like Silva's idea, frankly. But if you want to keep some of the atropal flavor:

Atropal, Fragment of Unmaking:

Since it's got all that NEP stuff anyway, why not jazz it up a bit? Voidstones are the ultimate manifestations of negative energy and cause disintegration effects on contact.

So homebrew up some extreme effects, place a couple voidstones around the atropal.

Effect 1: The voidstones disintegrate matter on contact. This includes air. A powerful vortex surrounds the atropal, drawing in the surrounding terrain. Fluff this as The Nothing from The Neverending Story to impress people of a certain age group and provide imagery. You can probably YouTube the scenes from that movie for narrative inspiration. Fluff-wise, I'd probably make it hurricane-strength. It deafens everyone in the radius, and even if they are protected from deafness, they still can't hear over the infernal din. Everything gets non-magical concealment, as dust, debris, trees, and everything is sucked toward the center of the vortex.

Not extreme enough? Make several vortices. As the characters enter areas of overlap near the atropal, opposing forces tear at them, doing non-magical damage and randomly bull-rushing them around with a high modifier (base it on the atropal's high stat). Ranged touch spells and other missiles likewise are affected, being thrown wildly off-course and affected as the atropal consumes even the magical energies that power spells.

Not extreme enough? The voidstones are sentient and have Su abilities equivalent to psion 20s, the amalgamated psychic detritus of all they have consumed. Proceed to deliver a beating worthy of the Tippyverse.

Effect 2: The voidstones consume air, meaning the area near the atropal (pick a round number, 30' or 60' are common) is airless and void, which I think the game establishes somewhere as dealing continuous cold damage.

Effect 3: The fabric of time itself breaks down near the atropal. Every few rounds (pick a number), the atropal gets a free non-magical, maximized time stop, essentially 5 free rounds of healing and self-buffing. To the characters, it literally looks like the thing teleports around, magically recovers, and otherwise can reestablish its defensive and prep new assaults.

The key to winning is to maneuver the atropal away from the more deadly area near the voidstones, trying to flush it out of its area.

This has more boss-fight flavor, is thematically undead without the minionmancy, and suitably epic visuals. It also makes the thing a bonafide threat to way more than just mortals, as it could conceivably wreck the entire Prime (or anywhere else) if it wanted to and was unopposed.

OK.
I can't properly respond to this because the forumn has rules about language.
But OMG wow.
Awesome.
Some questions. How do I deal with the ranger? Hurricane means wind, means her character is useless. And there isn't really anything she can do. I'd hate to just shut her down off the bat.

Ok. Voidstone. 60' Radius, 10d6 untyped void dmg, 10d6 Cold that overrides Immunity/Resistance fully.
If withing 30', Bull Rush towards closest. If impact, Fort DC... say...10+33(66hd)+16 (42 CHA) for 59 fort or Disentegrate? I think 3 of them in a triangle. Grants 50% miss chance due to windstorm. How do I represent airlessness? Drowning rules are shoddy...
I'm thinking I'll grant the Atropal Unholy Toughness, for some extra HP's.

Edit to your Edit.
Forgot about Entropomancer. Nifty class, I dig it. Having a Shard of nothingness definitely can add to the boss effect, its something they've never seen before. Sort of it's weapon of choice, so to speak. I can definitely make this work.

[Urpriest]

With the Atropal, remember it's got Rebuke/Command Undead as a level 72 Cleric. That means it can control two 34th level Necropolitan Wizards (or other undead casters with low turn resistance). If you want the Atropal to fight in an "atropal-ish" way, just give it enough minions capable of dispelling, since it seems like all of your party's protections against its core tactics are spell and/or item-based.