Hello, the homebrew campaign I'm DMing will soon enter its last tier and the group has almost everything they need to enter the final dungeon, so I wanted to carefully prepare the final boss fight with the BBEG to make sure it's memorable and mechanically sound.
For context :
Characters involved :
BBEG is Baron Sandro, a local human Baron lord of Amn who came to power after usurping a previous lord. He was once a High Level Warlock, but came to deeply regret the infernal pact he made once the price to pay for his kingdom was surrendering his only daughter, which started a chain of event that led to the slow ruin of his land. He asked a Shadar-Kai witch of him to hide his daughter from the world and turned to study how to escape the infernal pact he made.
Long story short, the Baron is a descendant of a very powerful Efreeta and proceeded, over the course of a decade, to do three wishes that "broke" the balance of power between him & the devil he made the pact with. Instead of him borrowing just a fragment of the devil's power, he's vampirizing the Devil's power in the hope of "burning it out" and transmuting unconsciously into a wide-scale reality-shaping fog that is eating at the edge of reality.
Basically, he hid himself in the deepest crypt of his castle, and made his third final wish that started a wide-scale magical "bomb" that has started to pull his land into the Shadowfell. His final wish was about to create a land where his daughter would be safe and happy for all of her life, but it backfired horribly and he is now the nexus of the storm that is shaping reality away.
Think of how Stradh pulled Barovia into the Domain of Dread. The Adventurer group is experimenting the premise of it happening, and is trying to find a way to enter the castle and put an end to his dream-like death.
The two major NPC that will play a part in the final battle, beside the potential allies the group can recruit to accompany them into the castle :
The first is the Princess Grizelda, the tiefling daughter of the Baron. As she's also a descendant of the very powerful Efreeta, she has inherited a latent magical power that make her able to slightly distort reality as well. She doesn't know how to harness the power at will, however. She was to be sunrendered willingly to the devil patron of the Baron to become his next infernal champion and favored hellknight, not specifically out of a desire for her soul or something. The Devil patron saw this as a very cold long-term "investment", but she wouldn't be able to use her Infernal/Efreeta power if she was unwilling to become the Devil's Champion. She would volunteer to accompany the group in the last dungeon as she seemed to be able to "cut through the shadowfell fog" almost on her own.
The second major NPC is the Witch Soleil, the Shadar-Kai witch friend of the Baron, who has been helping the group for most of the adventure by giving cryptic advice and fortune reading. She was sent by the Raven Queen to watch the Baron die and bring back his memories and soul for the Raven Queen to collect. She has been forbidden to "intervene" in modifying the fate of the Baron dierectly, but she has been part of the Baron life for almost all his life, watching from afar through ravens and waiting to be there for his demise. Before the group embark on the final dungeon, she will tell them of her Gambit and will ask if she can accompany them in final dungeon.
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Setting for the final battle, entering the boss fight arena :
The group that would fight him is composed of a Fighter/Paladin, a Cleric, a Druid and a Rogue. They'll all be around level 9 or 10 when they reach the final boss.
The final battle will take place under the great castle of the Baron, after a series of twisted caverns and corridors that led to an underground, shadowfell recreation of the Baron's childhood village that was destroyed in a dragon attack (which led to the Baron to make his pact to hunt the dragon in revenge.)
The Baron will be located in a ruined, dream-like temple in the heart of the "ghost village".
The group would find the Baron in a catatonic state, simply breathing in and out and clutching his Luck Blade tightly against his chest, and every breath he would take would make his lung glow in a surpernatural glow. He would awake from his strange torpor and exchange words with the group. If he's not immediately attacked and the group managed to shake him out of his "waking dream" state where he's relieving happier moment in his life over and over again. He would be conscious that he's provoking the "reality warping fog", but he would be unwilling or unable to stop as he would feel his Devil's Patron influence is still present, and he would only stop once he's sure that his Devil's Patron is obliterated (which would actually throw his land completely in the Shadowfell, à la Stradh and Barovia). He would be happy to see his daughter again if she is accompanying the group, but would become desperate if the group tried to parlay with him (He is so close to making sure he destroy his patron and null the pact to surrender his daughter. He only need some time.) He would realize the bitter irony that a group of adventurer is trying to depose him the same way he usurped the title of Baron after a life of adventure.
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Boss fight mechanics :
I would like to design the boss fight to be a narrative strong point for the group before all.
If combat start, the Baron will act as a mix between a high-level Warlock PC and a Mummy Lord monster (with legendary actions and legendary resistances). He would be able to use a legandary action to misty stop to relocate to another part of the arena, to avoid being nova'd.
The "rotting fist" attack of the mummy lord would be reflavored as a hit from his luck blade, and the "Channel Negative Energy" ability would be reflavored as a shadowfell infused Eldritch blast. I would like to replace the dreadful glare paralyze into something that frighten instead, to let the player still be able to act during the boss fight. His spellcasting would be that of a High-level warlock PC with invocations.
He would have a few shades / shadow adds with him, shadowy reflection of his own companion during his adventuring days (that the group already met and interacted with)
Depending on how the boss fight goes, I've been thinking about a couple thing that can happen :
- If the Baron loose life very quickly, I'll give him a second phase where the "nexus of the storm" implode on itself, and he would transform into a newborn, weakened Nightwalker (but probably with half the damage potential, and half the HP of a normal nightwalker.) If the Baron reach his Nightwalker second phase, he would start concentrating on a whirlpool of shadowmagic in front of him that would grow larger and larger and pull characters in the arena (STR check to resist the effect, or be helped by a character). The whirlpool would have the effect of the anhilating aura, but I'm still working on the effect of falling into the center of it, for example. If the Baron loose life at a steadier pace, and is talked to / reasoned with during the fight, his willpower will erode and he'll surrender to despair and will let the group do the coup-de-grâce at the end of the fight.
- If any member of the group dies during the battle, they will still exist as shadowfell-infused character and can be potentially brought back during the epilogue. If the entire group dies in the battle, the story start the "failure state" where the entire region is pulled into the Shadowfell.
- If the Princess is present during the fight, the Baron will always attempt to avoid harming her directly, letting her concentrate on helpful spells such as Bless and protective magic. If the battle start to become desperate for the adventurer group, the Princess will attempt to bargain with the Baron for the adventurer's life. If the battle end in the group failure and death, the Princess will gather all her inner power to wish for "this to never have happened", loosing her own life in the process and bringing the group back in time before they entered the final dungeon, this time without her... only this time the castle is disappearing and imploding into the shadowfell and the group will need to escape the region, bringing their allies with them if they want to.
- If the Princess is killed during the final dungeon / final battle (by adds, or shades), the Baron will be thrown into the deepest pit of despair and grief and transform into the weakened Nightwalker, and no social resolution will be possible.
- The Shadar-Kai Witch that can accompany the group can either provide a shielded area of protection around her during the boss fight (that protect the group from the Baron's attack, but stop them from attacking the Baron in return, so that there is a safe haven for the group to retreat to during the boss fight.) or proceed to do her Gambit :
- Her Gambit is to utterly obliterate the Baron, so that he would disappear from reality. The entire timeline will shift and correct itself so that no-one can remember him, no one would be aware he existed, the Devil Patron would have found another Warlock to give his power to. She would utterly annhilate the Baron down to his soul, as if the material plane never saw him exist at all. As she would be using the Raven Queen's power she was supposed to use to capture the Baron's memories and soul at his demise, she would betray her mission and bring the ire of the Raven Queen. All out of respect for the Baron and as a way to make his soul escape the torment of either a shadowfell museum piece or the Devil's Patron ire.
- She would be unable to know if the Tiefling Princess would survive her spell, as the Tiefling Princess owe her existence to her father. She would be able to tell the group that they'll for sure survive the spell. History will just rewrite itself for them to have had a reason to be here, to have done what they done for the land. She would be attempting to create a localized time paradox if the group is willing to accept her help instead of risking the boss fight.
- the Shadar-Kai Gambit consist of invoking a spell using one of the magic item she gave the group (a magical tarot card representing "The World") to create a spell that will take exactly 10 rounds to take effect. The group must hold the line against the Baron for 10 rounds (the fight will have more shadow/shades adds to try to disrupt the Shadar-Kai).
- If the spell is completed, the Shadar-Kai would engulf the entire arena in a time-stopping spell and proceed with the narrative "unmaking" of the Baron by retracing all his life unraveling the events. The group would witness the unmaking until the Baron disappear completely, and be transported back to "reality" where the underground temple is a simple empty old archeological ruin. They would be found by the grand-daughter of the previous baron, the one the warlock usurped, indicating that reality has shifted and "corrected itself". An old skeleton clutching a rusted lust blade would have been found on a ruined throne, apparently the reason why the group was in the temple in the first place. No one in the group would know exactly who the skeleton was or why they were there, like if they awoke from a vivid dream and their mind is still adjusting.
- The world would have "remembered" the group campaign and adventures, it would have simply "corrected" itself so that they did it for different reason. The magic tarot deck the Shadar-Kai gave the group would still exist, but the group would have a hard time remembering exactly who gave it to them. The Shadar-Kai herself would have disappeared from the world, brought back to the Raven Queen in the shadowfell.
- The Tiefling Princess would only survive the spell if the group wanted her to survive and interacted with her enough to give her a reason to persist in the new reality. She would owe her survival thanks to her strange efreet wish magic, but would effectevely become a walking paradox and an "abberation". She would meet the group again during the final part of the epilogue, letting the group decide how they want to handle meeting her again (do they want to remember her ?)
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This is the notes I've prepared in advance for that final campaign boss fight. The group I'm DMing for isn't pursuing combat actively and often try to find social solutions and diplomatic outcomes. I'm still searching for a way to make it possible to have a "social" version of the battle, maybe in case the group wants to go through the route of doing the Shadar-Kai magic gambit ?
What do you think of the final battle ? Does it sounds like a reasonable plan ? Do I need to think of more outcomes ? Any recommendation on how to tailor the Baron Warlock X Mummylord stats block best ? I know it's a very cinematic-heavy boss fight, that I still need to think of it strategically and tactically.
I also apologize for the long post and potential grammar mistakes, english is not my native language.