So, my players are going to war against a Yuan Ti city. Boss Fight help.

[Rolero]

Hello, as the title says, after weeks of play exploring a remote jungle, my pc were captured by the Yuan Ti. They discovered a huge ancient city of them, so killing them all by themselves was out of the question. After a daring, and very fun to play, escape from their prisson, they went out through an abandoned underground tunnel, where they were able to reach the jungle and flee with lots of rescued prisoners. With the Yuan Ti on their heels they were ultimately rescued by a flying ship of a powerful npc they've helped in the past and have contacted previously via sending.

A bunch of exposition to this npc and their allies follows about the dangers of the Yuan Ti, especially with their current situation. My campaign occurs in an archipielago of uncharted islands and the island where this ancient city was discovered is the same where the empire this npc belongs has built their settlement. Not much later they discovered some pure-blood yuan ti spies posing as citizens. So, this empire decides is time to take action and clean their island of its "pest" for good.

War preparations ensues, giving my pc two weeks of downtime to ask their contacts for help, prepare for the conflict and decide how will they engage in the fight. After a week, they went to talk with the general of the empire that will command the operation from the flying ship and offers the pc a possible plan of action. The army will fight the bulk of the yuan-ti numbers, while the pc infiltrate the temple where their leader resides and take him out.

My players accepted the deal, and will try to enter the city through the same tunnels they used for their escape during the battle.

I don't plan to give them to much trouble with the covert operation, being the focus of the sesion the temple assault and the fight against the boss.
I have the map (a modified version of the one in Volo's), some ideas for traps and general encounters, but I wanted some help for the boss.

The leader of the city is trying to become an Anathema through a "plot device" ritual. He is Mind Whisperer, which at this point is not a challenge to the party as a boss. So, my dilemma is how to power him up for him to be accordingly powerful for his possition, or, just present him transformed.

For reference, this is my party of pc:
-Human Vengange Paladin 5 / Blade Fiendlock 3
-Tabaxi Lore Bard 8
-Human Evoker Wizard 7
-Human Shadow Sorcerer 7
-Half-Orc Arcane Knight 6 / War Cleric 1

Both the Wizard and the Sorcerer tend to blast everything around with fireballs. Then the Palalock comes in and smite the remains while the Bard buff and debuff. The Arcane Knight is a recent adition (was a moon druid but wanted to try something different) and will try to focus on tanking.

They are a solid group, so I want to give them a memorable final fight to close this chapter of the campaign with a bang.

So, I plan to have some fights in the temple, some cultist, snake swarms, pure-blood, broodguards and maybe abominations or nightmare speakers, depending on how well they are doing.

Then, the boss battle. An Anothema may be too much for them if they are too weakened, but if not, the action economy will eat the beast down in seconds. I could toss in legendary actions and saves, some lair actions even, but I am not quite sure which ones, I am very open to suggestions.

Another take could be the power up version of the Mind Whisperer, but again, not quite sure how to implement that while maintaining balance.
I would actually prefer this version of the guy, having my players get in the nick of time to prevent his ritual and have a climatic battle against the clock to stop it before its too late (they only know he is trying to become a god). This way, I will also include some minions as fodder to balance the numbers of actions of the enemy party.

In any case, I am open to suggestions, builds and whatever idea you may have for this boss fight. Thanks in advance.

[DrKerosene]

If you want to “power up” the Whisperer, could you just take the Warlock Of The Fiend around page 220 and apply the PC Yuan-Ti racial stats? Maybe swap a few spells.

It’s probably not going to survive that much longer without having a few CR 1/4 (or CR2) casters stacking buffs onto the Warlock Whisperer. A handful of Apprentice Wizards, or Cult Fanatics should be able to stack some buffs on your boss if you tweak thier spell lists.

I suppose you could also use the AngryDM method of “paragon monsters” to increase actions per round and total HP.

[Darkstar952]

I had my players encounter an Anathema at level 8, it had a few Malisons and Purebloods as a retinue. The group managed to come through the fight, one PC dying.

The situation was slightly different as the group were defending a temple site with Yuan-ti attacking. and was complicated with two of the players dimension dooring into the boss encounter early, and the other players having to race to catch up.

Made for a very memorable and challenging encounter.

[Dungeon-noob]

They're attacking the leader of a city: they should be the ones outnumbered, not the other way around. A dozen purebloods and broodguards should go a long way. Also consider throwing down some battlefield control and then a silence spell, considering the opponents know this party is extremely heavy on the casting side. Or bring a counter-speller or two. I also expect several ambushes on the way there, a mind wisperer is supposed to be the sneakiest type. Getting to this mastermind should be the challenge, not killing him in a straight fight. This is a sneaky sneaky snake bastard who doesn't care to play fair. Using hostages might also be interesting.

I might have more ideas later, but this seems like enough to think about for now. Remember, a mind wisperer is more Kira or Royal visier then demon lord or dragon. Less straight on personal power, more tons of minions, plots, intelligence and schemes.

[Rolero]

If you want to “power up” the Whisperer, could you just take the Warlock Of The Fiend around page 220 and apply the PC Yuan-Ti racial stats? Maybe swap a few spells.

It’s probably not going to survive that much longer without having a few CR 1/4 (or CR2) casters stacking buffs onto the Warlock Whisperer. A handful of Apprentice Wizards, or Cult Fanatics should be able to stack some buffs on your boss if you tweak thier spell lists.

I suppose you could also use the AngryDM method of “paragon monsters” to increase actions per round and total HP.

Not a fan of including homebrew material in the campaign. And while it has some interesting ideas, I'm not convinced. Maybe I'll try this rules on an unique monster, not as a usual boss fight. Thx for the imput though.


They're attacking the leader of a city: they should be the ones outnumbered, not the other way around. A dozen purebloods and broodguards should go a long way. Also consider throwing down some battlefield control and then a silence spell, considering the opponents know this party is extremely heavy on the casting side. Or bring a counter-speller or two. I also expect several ambushes on the way there, a mind wisperer is supposed to be the sneakiest type. Getting to this mastermind should be the challenge, not killing him in a straight fight. This is a sneaky sneaky snake bastard who doesn't care to play fair. Using hostages might also be interesting.

I might have more ideas later, but this seems like enough to think about for now. Remember, a mind wisperer is more Kira or Royal visier then demon lord or dragon. Less straight on personal power, more tons of minions, plots, intelligence and schemes.

Oh, he knows they are coming, but he is also very focused on the ritual and with an army at the city gates I'll rule that he will be a little distracted, centering his efforts in becoming the god he wants to be.

There is a hostage though: a captured guardian naga, which is part of the macguffin ritual (basically a sacrifice). She has info the pc wants about the campaign plot. My idea is having a time limit to finish the fight and stoping the ritual, if not, the villain will make it to godhood and they'll be scr***d.

I also thought about using this ritual as a lair action, e.g.: energy drain from the naga to be sacrificed that heals the big baddy.
Other choices could be arrival of fresh fodder (purebloods or broodguards only)

In the end, I think I'll try to buff up the Mind Whisperer base stats and give him 1 legendary action and 1 legendary save. I want him to be a better warlock, so I'll upgrade him with the Warlock of the Fiend stats of Volo's changing some spells to make it more mastermind like.

A rule of thumb I follow with bosses is maxing out their HP, so he will have 120hp, which I think is very respectable.

I'm thinking of having 4 purebloods, 2 broodguards and 2 malison with him during the ritual. The Purebloods will attack with their bows, while the broods and malison engage in melee while the boss stays behind casting. I may include swarms of poison snakes getting into the fray through the walls.

Thoughts? Do you think it will be too much?

[Dungeon-noob]

Not a fan of including homebrew material in the campaign. And while it has some interesting ideas, I'm not convinced. Maybe I'll try this rules on an unique monster, not as a usual boss fight. Thx for the imput though.



Oh, he knows they are coming, but he is also very focused on the ritual and with an army at the city gates I'll rule that he will be a little distracted, centering his efforts in becoming the god he wants to be.

There is a hostage though: a captured guardian naga, which is part of the macguffin ritual (basically a sacrifice). She has info the pc wants about the campaign plot. My idea is having a time limit to finish the fight and stoping the ritual, if not, the villain will make it to godhood and they'll be scr***d.

I also thought about using this ritual as a lair action, e.g.: energy drain from the naga to be sacrificed that heals the big baddy.
Other choices could be arrival of fresh fodder (purebloods or broodguards only)

In the end, I think I'll try to buff up the Mind Whisperer base stats and give him 1 legendary action and 1 legendary save. I want him to be a better warlock, so I'll upgrade him with the Warlock of the Fiend stats of Volo's changing some spells to make it more mastermind like.

A rule of thumb I follow with bosses is maxing out their HP, so he will have 120hp, which I think is very respectable.

I'm thinking of having 4 purebloods, 2 broodguards and 2 malison with him during the ritual. The Purebloods will attack with their bows, while the broods and malison engage in melee while the boss stays behind casting. I may include swarms of poison snakes getting into the fray through the walls.

Thoughts? Do you think it will be too much?
All sounds fine. Just make sure there are enough encounters/guards on the way there and it sounds like you're set.

[Droodicus]

I'd have the ritual culminate on the top of a pyramid while the party is battling their way up. Then have a cool ah no to late moment when it becomes an anathema. Have a plan to buff/debuff the anathema depending on how battered the party is.
Example. The party novas it down too soon, use its reaction to draw a massive pile of hp back from all the sacrifices that are scattered on the altar.
Party's getting in tpk danger zone and you don't want to kill all of them, have it sicken scales sloughing off, head drooping, etc. Oh no you forced it to rush the ritual so it's not working 100%

[Rolero]

I like the idea of the rushed ritual!

If they are too late or the fight goes for two long, It can happen and have the boss in "this isn't even my final form" mode ^^

My plan is for the ritual to take 10 combat rounds to be ready, and then one more to actually work, so they have one final chance to stop it.

This is what I've come up to for the boss. Mix of Mind Whisperer, Fiend Warlock Stats but with Great Old One spells:

Medium monstrosity (shapechanger, yuan-ti), neutral evil
Armor Class 15 (Mage Armor) Hit Points 120 (12d8 + 24) Speed 30 ft.
STR 16 (+3)
DEX 14 (+2)
CON 14 (+ 2)
INT 16 (+3)
WIS 16 (+3)
CHA 16 (+3)
Saving Throws Wis +6, Cha +6
Skills Deception +6, Intimidation +6, Persuasion +6, Percepcion +6, Insight +6, Stealth +5
Damage Immunities poison Condition Immunities poisoned
Senses darkvision 120 ft. (penetrates magical darkness), passive Perception 15
Languages Abyssal, Common, Draconic

Shapechanger. The yuan-ti can use its action to polymorph into a Medium snake or back into its true form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. If it dies, it stays in its current form.

At will: animal friendship (snakes only) 3/day: suggestion

Magic Resistance. The yuan-ti has advantage on saving throws against spells and other magical effects.

Mind Fangs (2/Day). The first time the yuan-ti hits with a melee attack on its turn, it can deal an extra 16 (3dl0) psychic damage to the target.

Seth's Blessing. When the yuan-ti reduces an enemy to 0 hit points, the yuan-ti gains 9 temporary hit points.

ACTIONS
Multiattack (Yuan-ti Form Only). The yuan-ti makes one bite attack and one scimitar attack.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (ld4 + 3) piercing damage plus 7 (2d6) poison damage.
Scimitar (Yuan-ti Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft;, one target. Hit: 6 (ld6 + 3) slashing damage.

LEGENDARY ACTIONS
He has 1 legendary action per turn:
-He moves without provocing AoO
-He cast a Cantrip
-He makes an attack

LAIR ACTIONS
Occur on Iniative 20, with one of the following options:
-HP is drained from the sacrifice, healing 2d10 HP to him
-He recovers an expended spell slot.

LEGENDARY SAVE
1/day: When he would fail a saving throw he can choose to succeed.

Innate Spellcasting. The warlock's innate spellcasting ability is
Charisma. It can innately cast the following spells (spell save DC 16),
requiring no material components:

At will: Alter self, False life, Levitate (self only), Mage armor (self only), Silent image

1/day each: Investiture of Flame, Power Word Pain

Spellcasting.
Its spellcasting ability is Charisma (Spell save DC 14, +6 to hit with spellattacks).
It regains its expended spell slots when it finishes a short or long rest.
It knows the following warlock spells:

Cantrips (at will): Eldritch blast, fire bolt, Friends, Mage hand, Minor illusion,
Prestidigitation, Shocking grasp

1st-5th level (x4 5th-level slots):
1st Dissonant Whispers, Sleep
2nd Suggestion, Misty Step, Detect Thoughts, Phantasmal Force
3rd Stinking cloud, Clairvoyance, Sending, Counterspell
4th Dominate Beast, Scrying, Evard's Black Tentacles
5th Dominate Person, Telekinesis

Dark One's Own Luck (Recharges after a Short or Long Rest).
When the warlock makes an ability check or saving throw, it can add a d10 to the roll. It can do this after the roll is made but before any of the roll's effects occur.

The lair action represents the ritual gradual empowerment.
One doubt though, maybe casting a cantrip as legendary action is too op? (EB: 3x attacks +6 to hit/1d10+3 dmg)

[Keravath]

Just remember that almost all the yuan-ti have magic resistance.

Rolling their saves vs spells and magic with advantage can go a long way to reducing the impact of spellcasters. Add in a couple of yuan-ti who can counterspell (it is only a 3rd level spell available to 5th level warlocks) and you can probably reduce the effectiveness of fireballs and hypnotic pattern even further.

Since this is a city of yuan-ti and your description included so many that the neighbouring empire is fielding an entire army to deal with them. It would be completely normal for the boss to have at least a couple of dozen guards and sycophants protecting and participating in the ritual (6-8 is unrealistically small in my opinion). The city (from your description) has hundreds of yuan-ti ... the boss would have to be incredibly stupid to leave his personal guard at a very low level during such a crucial ritual unless your players can do something to draw off some of the guards. You might want to emphasize to them that they will need a GOOD plan.

Perhaps have the defence of the boss at the end dependent on what actions the PCs take to draw off the usual guards and reduce the defending numbers. If they just waltz into the ritual without some plan except kill/smash then they should have a much harder time than if they apply some strategy, create distractions and confusion, draw off some of the defenders (since they need to be convinced that forces are coming from a different direction that could prevent the ritual ... there is no other reason these guards would leave).

Finally, you can have the opponents engage in waves. If the battle is going very well for the PCs then perhaps have some of the guards either return from a distraction or come out of hiding and engage the party from an unexpected direction. On the other hand, if the party is having trouble those reinforcements could be delayed or drawn off for other reasons.

[Rolero]

Just remember that almost all the yuan-ti have magic resistance.

Rolling their saves vs spells and magic with advantage can go a long way to reducing the impact of spellcasters. Add in a couple of yuan-ti who can counterspell (it is only a 3rd level spell available to 5th level warlocks) and you can probably reduce the effectiveness of fireballs and hypnotic pattern even further.

Since this is a city of yuan-ti and your description included so many that the neighbouring empire is fielding an entire army to deal with them. It would be completely normal for the boss to have at least a couple of dozen guards and sycophants protecting and participating in the ritual (6-8 is unrealistically small in my opinion). The city (from your description) has hundreds of yuan-ti ... the boss would have to be incredibly stupid to leave his personal guard at a very low level during such a crucial ritual unless your players can do something to draw off some of the guards. You might want to emphasize to them that they will need a GOOD plan.

Perhaps have the defence of the boss at the end dependent on what actions the PCs take to draw off the usual guards and reduce the defending numbers. If they just waltz into the ritual without some plan except kill/smash then they should have a much harder time than if they apply some strategy, create distractions and confusion, draw off some of the defenders (since they need to be convinced that forces are coming from a different direction that could prevent the ritual ... there is no other reason these guards would leave).

Finally, you can have the opponents engage in waves. If the battle is going very well for the PCs then perhaps have some of the guards either return from a distraction or come out of hiding and engage the party from an unexpected direction. On the other hand, if the party is having trouble those reinforcements could be delayed or drawn off for other reasons.

A good point.

Through past experiences they have learn (the hard way) that scouting and being smart in their aproach is better that going in guns blazing. Of course, their usual tactics described above are in play when they opt for the direct confrontation. I expect them to be carefull as they have seen first hand what they are up to.
Depending on how they handle it, the number of minions I posted before could be more or less, and probably adding or reducing the pure blood only.

[Vogie]

One doubt though, maybe casting a cantrip as legendary action is too op? (EB: 3x attacks +6 to hit/1d10+3 dmg)

Change it to a casting of Firebolt or Shocking Grasp, then it's just 1 attack.

I'm a huge fan of making bosses triggering an effect when they hit half health, a la the Bloodied condition of yore, or the enrage effects of MMORPG.

I'd make the enrage/bloodied/half health hit be a casting of EB with Repelling blast, auto-hitting 3 targets and pushing them back 10 feet.

And since you have a lair action heal, there's a chance it could trigger twice.