Charles Rampant
Adventurer
Hey all,
When the next session of my campaign takes place, we'll be rolling initiative for the most monstrously complex (and unfair) fight that I've put my players up against yet. I'm coming to you for help in ensuring that I made interesting and fun choices for the bad guys. Let me begin by outlining the situation.
Outline
The players are in Tu'Narath, home to the Githyanki, and have fought their way into the throne room of the Lich Queen Vlaakith CIX. This is from the 3rd edition adventure Lich Queen's Beloved. She's perfectly aware of who they are, and has been scrying on them enough to have a good understanding of their abilities and tactics. The characters were greeted by Vlaakith, who offered them the chance to achieve all their goals (free some slaves) and leave without repercussions, but they decided to go for combat instead. They didn't want to leave her - a powerful lich - alive, and also didn't want to 'get a reputation as quitters'. They made that choice in the full knowledge that this fight is likely to be a TPK, so I deem that I can take the gloves off and go for the kill, within reason.
The opposition here is really, truly, punishing: in addition to a CR25 Lich (all wizard spells known, 473hp), there is two 16th level undead spellcasters (same spell list as a Lich), two CR10 spectral Githyanki Knights, and two Adult Red Dragons without wings. The EXP here is 162,800, with a difficulty after modifiers of 407,000. In other words, 8x Deadly for a party of this size and level. Hopefully a file will be inserted below here which shows the layout of the room - enemy along the left wall, a dragon to the top and bottom, party on the right, and a necrotic-damage spell trap in the centre of the room. Miscellaneous magical effects in the location include no invisibility, everyone can fly at the speed of their Intx3, everything has resistance to radiant damage.

The Party's Plan
They are 19th level: Storm Cleric, 4Elements Monk, Devotion Paladin, Champion Fighter Archer, Arcane Trickster. No sharpshooter on the Champion. Their plan is to use a 8th level Cleric slot and the monk's Ring of Wishes to cast two Antimagic Fields, and use them to neuter the Lich and at least one of her spellcasters. They'll move into melee and grapple to try and make it stick. The Paladin will dual-cast Banishment on the Dragons to try and get rid of them. Then everyone will try and nuke down the Lich first.
Antimagic field is a complex spell: here is a blog post discussing it and giving the spell's text. The party expects that they'll lose the ability to kill the Lich in melee (no magic weapons, she's immune to non-magic weapons) except for the Monk and his magic fists.
Enemy Plan
My baseline plan was for Vlaakith to use True Polymorph on herself (not Meteor Swarm, which the party are expecting) and to try to use an Ancient Silver Dragon's breath weapon to paralyze the whole party, especially those that normally avoid Red Dragon breath weapons with evasion. If that failed, she'd at least have loads of free HP. Once knocked out of that shape, probably Forcecage would be my next step, but I'm wary of it since the party cannot do anything about it - no arcane caster so no friendly short range teleport options, and it isn't even concentration. It seems likely to be unfun, so I didn't want to open with it. The two spellcasters would just use Finger of Death and whatnot to try and chip away at the party, and the Dragons would wade into melee.
As to the party's plan, it seems to me to be very devious. The Dragons are unlikely to fail against Banishment - since they have +11 on Cha, even if I ignore their Legendary Resistance as they're really not the boss here - but the Antimagic fields are the killer. Once those are cast, I can see only two routes for Vlaakith and her minions: either fight in melee to try and break concentration, or use Counterspell at the moment of casting to shut it down. Having her do Counterspell would almost certainly work - the party can't cast that themselves - but seems like a bit of a dick move to arbitrarily negate what is actually an interesting tactic.
My Question to you
What should I have the bad guys do? I wouldn't normally come to a forum for answers on how to handle a party's tactics, but like I say, it's a big one. In addition, this is probably going to be the biggest fight in the campaign as a whole, which has run from 1-20, so I want it to stick in the mind whether it's won or lost.
Part of my mind is to let the party try the anti-magic, and not counterspell it or whatnot; the fight is insanely tough anyway, so letting good play negate the Lich isn't a bad thing, and the monk alone will struggle to strip 473hp from her in melee. However, it's worth asking ya'll what you think about it, and seeing whether I've missed any more interesting options.
When the next session of my campaign takes place, we'll be rolling initiative for the most monstrously complex (and unfair) fight that I've put my players up against yet. I'm coming to you for help in ensuring that I made interesting and fun choices for the bad guys. Let me begin by outlining the situation.
Outline
The players are in Tu'Narath, home to the Githyanki, and have fought their way into the throne room of the Lich Queen Vlaakith CIX. This is from the 3rd edition adventure Lich Queen's Beloved. She's perfectly aware of who they are, and has been scrying on them enough to have a good understanding of their abilities and tactics. The characters were greeted by Vlaakith, who offered them the chance to achieve all their goals (free some slaves) and leave without repercussions, but they decided to go for combat instead. They didn't want to leave her - a powerful lich - alive, and also didn't want to 'get a reputation as quitters'. They made that choice in the full knowledge that this fight is likely to be a TPK, so I deem that I can take the gloves off and go for the kill, within reason.
The opposition here is really, truly, punishing: in addition to a CR25 Lich (all wizard spells known, 473hp), there is two 16th level undead spellcasters (same spell list as a Lich), two CR10 spectral Githyanki Knights, and two Adult Red Dragons without wings. The EXP here is 162,800, with a difficulty after modifiers of 407,000. In other words, 8x Deadly for a party of this size and level. Hopefully a file will be inserted below here which shows the layout of the room - enemy along the left wall, a dragon to the top and bottom, party on the right, and a necrotic-damage spell trap in the centre of the room. Miscellaneous magical effects in the location include no invisibility, everyone can fly at the speed of their Intx3, everything has resistance to radiant damage.

The Party's Plan
They are 19th level: Storm Cleric, 4Elements Monk, Devotion Paladin, Champion Fighter Archer, Arcane Trickster. No sharpshooter on the Champion. Their plan is to use a 8th level Cleric slot and the monk's Ring of Wishes to cast two Antimagic Fields, and use them to neuter the Lich and at least one of her spellcasters. They'll move into melee and grapple to try and make it stick. The Paladin will dual-cast Banishment on the Dragons to try and get rid of them. Then everyone will try and nuke down the Lich first.
Antimagic field is a complex spell: here is a blog post discussing it and giving the spell's text. The party expects that they'll lose the ability to kill the Lich in melee (no magic weapons, she's immune to non-magic weapons) except for the Monk and his magic fists.
Enemy Plan
My baseline plan was for Vlaakith to use True Polymorph on herself (not Meteor Swarm, which the party are expecting) and to try to use an Ancient Silver Dragon's breath weapon to paralyze the whole party, especially those that normally avoid Red Dragon breath weapons with evasion. If that failed, she'd at least have loads of free HP. Once knocked out of that shape, probably Forcecage would be my next step, but I'm wary of it since the party cannot do anything about it - no arcane caster so no friendly short range teleport options, and it isn't even concentration. It seems likely to be unfun, so I didn't want to open with it. The two spellcasters would just use Finger of Death and whatnot to try and chip away at the party, and the Dragons would wade into melee.
As to the party's plan, it seems to me to be very devious. The Dragons are unlikely to fail against Banishment - since they have +11 on Cha, even if I ignore their Legendary Resistance as they're really not the boss here - but the Antimagic fields are the killer. Once those are cast, I can see only two routes for Vlaakith and her minions: either fight in melee to try and break concentration, or use Counterspell at the moment of casting to shut it down. Having her do Counterspell would almost certainly work - the party can't cast that themselves - but seems like a bit of a dick move to arbitrarily negate what is actually an interesting tactic.
My Question to you
What should I have the bad guys do? I wouldn't normally come to a forum for answers on how to handle a party's tactics, but like I say, it's a big one. In addition, this is probably going to be the biggest fight in the campaign as a whole, which has run from 1-20, so I want it to stick in the mind whether it's won or lost.
Part of my mind is to let the party try the anti-magic, and not counterspell it or whatnot; the fight is insanely tough anyway, so letting good play negate the Lich isn't a bad thing, and the monk alone will struggle to strip 473hp from her in melee. However, it's worth asking ya'll what you think about it, and seeing whether I've missed any more interesting options.