[MENTION=12731]CapnZapp[/MENTION] Love the
reverse gravity and lava idea!
Before sharing my mad plans, I wonder if your party is already so potent that giving them +50 temporary HP bonus might be too much. My understanding is that bonus is meant to bridge the gap between a non-fresh 4-to-5 person 9th-11th level party and Acererak...particularly to act as a buffer against
power word kill IIRC you have a 6-person party and that they're pretty potent for 14th level characters. Maybe you can cut out the temporary hit points?
Anyhow...
I'm also running ToA, though my party's 6th level and hasn't yet reached Omu, so what I have to offer are just my own thoughts. I read the same blogs and Reddit posts, but I wanted to see what I could come up with using his spells as written in ToA before going the route of selecting a different spell load-out. It involves stretching the rules a very little bit (using the lich phylacteries as narrative justification) & may be insufficient for your needs. But maybe there will be useful bits. Here's what I came up with...
In Advance:
Acererak casts
mind blank on himself, which lasts 24 hours, making him immune to being charmed (he’s already immune), psychic damage (including the +3d6 psychic damage the trickster gods grant PC attacks), divination magic, or other effects reading his thoughts/emotions. On its own, this is a bit niche, but it blocks that extra damage, could come in handy if someone tries
detect thoughts, and would be even better if paired with
greater invisibility, since
mind blank causes ALL divinations (like
see invisibility) to fail in regards to Acererak.
I imagine that he enters the Tomb via a portal or artifact or something else that doesn't require expending a spell slot. I also imagine that he hasn't used any spell slots prior to the confrontation, with the exception of
mind blank.
Acererak can cast animate dead as a legendary action, an exception to the usual casting time rules (wherein it takes 1 minute). Additionally, I'd rule that he can use an upcast animate dead as a legendary action, since it's still the same spell. The northern wall in the Death God's Nursery has alcoves full of bones, like an ossuary. I think you could have any sort of reasonably-sized skeletons climbing out of there... minotaur skeletons might be better suited to your experienced party, are on theme, and their ability to force movement pairs viciously with the lava. Skeletons should pour from the northern wall. Too many skeletons and they might push the PCs into the lava! Who focuses on skeleton population control & who goes right for Acererak? I believe that's part of the intended tension built into the final showdown and is foreshadowed with the Tomb's grisly construction.
Round #1: Open/Close the Door
ACTION:
time stop, 1d4+1 turns: (1) move Sphere of Annihilation among a cluster of PCs, (2) cast
wall of force around those clustered PCs, (3) cast
mage hand to close the Skeleton Gate*, (4) cast
arcane lock on the Skeleton Gate* (if he doesn’t get to cast mage hand and arcane lock, have him do so on Round #3 or #4), (5) Invoke Curse (upon whoever killed the atropal)
LEGENDARY (x1):
animate dead @7th level = 9 skeletons*
LEGENDARY (x2): use Talisman of the Sphere (4d10 force damage) to move Sphere of Annihilation among clustered PCs
REACTION:
shield or
counterspell (he keeps a 4th level and 5th level spell slot available for upcasting
counterspell)
An asterisk (*) indicates a spell which I'm using in a way that breaks RAW, mostly in regards to range. For example, animate dead has range 10 feet, but Acererak's balcony is more like 60 feet from the northern wall with the bone alcoves. Down below I describe how I'm planning on making the lich phylacteries act like "bennies" allowing Acererak to tweak his spells slightly...kinda like Metamagic. PCs can devote actions to destroying lich phylacteries (a whole other story) to reduce Acererak's access to these "bennies."
Round #2: Curses and Spheres
ACTION: Invoke Curse (used upon whomever delivered the killing blow to the atropal)
BONUS ACTION: command undead
LEGENDARY (x1):
animate dead @6th level = 7 skeletons
LEGENDARY (x2): use Talisman of the Sphere (4d10 force damage)
REACTION: shield or counterspell
Round #3: Electrified, Mortified
ACTION:
chain lightning
BONUS ACTION: command undead
LEGENDARY (x1):
animate dead @6th level = 7 skeletons
LEGENDARY (x2): Frightening Gaze
REACTION:
shield or
counterspell
Round #4: Get on the Floor
ACTION:
maze... OR... if his previous
wall of force has dropped and you see a golden opportunity... he might cast
wall of force upon the floor, creating a sort of disco pattern of translucent lights upon it (and summoned skeletons will use the
wall of force "floor" to attack the PCs)...but the minute a PC is on the "floor" over the lava at the end of Acererak's turn, he ends concentration on the wall as a legendary action.
BONUS ACTION: command undead
LEGENDARY (x1):
animate dead @5th level = 5 skeletons
LEGENDARY (x1): Paralyzing Touch
LEGENDARY (x1):
ray of sickness (cast at whomever he’ll cast maze upon to impose disadvantage on their save)
REACTION:
shield or
counterspell
Round #5:
ACTION:
power word kill
BONUS ACTION: command undead
LEGENDARY (x1):
animate dead @4th level = 3 skeletons
REACTION:
shield or
counterspell
Round #6:
ACTION:
finger of death (cast on cursed target)
BONUS ACTION: command undead
LEGENDARY (x3): Disrupt Life
REACTION:
shield or
counterspell
Optional: Lich Phylacteries
The lich phylacteries in the Death God's Nursery are left as background flavor in ToA, but the present a golden opportunity to introduce a narrative justification for Acererak to tweak his spells to make for a more engaging & challenging confrontation. Whenever Acererak casts a spell, as part of the spellcasting he may drain the power from one lich phylactery to twist his spell in a small way. Each lich phylactery he drains (thus destroying it) allows him to augment one spell. Some examples include:
- Cast animate dead at 100 ft range, instead of 10 ft, allowing him to cast it upon the bone-filled alcoves in the northern wall.
- Cast animate deadwith a 7th level spell slot to animate a minotaur skeleton (450 XP) instead of 9 skeletons (50 XP each). Though, for your purposes, you might let Acererak drain a phylactery to cause ALL skeletons he animates to be minotaur skeletons.
- Cast planeshift or teleport, circumventing the magical conditions teleporting the creature(s) to Area 57. Just a bit of narrative justification for how Acererak circumvents the Area 57 trap.
- Cause a spooky effect, such as a skull in the northern wall whispering tauntingly to a PC or cracking a morbid joke. Because Acererak is a dick.
- Extend the range of mage hand to reach the Skeleton Gate. I might narrate this as the goblin skeletons worked into the gate animated to close it behind the PCs.