Domina Tenebris

Welcome to Tenebris

A scream shatters the still gloom. Inhuman shapes slip between crumbling tombs. The shadows reach forth. A black feather rests at your feet. Do instincts and imagination conspire against you? Or have otherworldly forces claimed you, drawing you into the Mists?
In the hidden corners of the realms, there exists nightmarish domains that hunger for the brave and the innocent, the ambitious and the wicked, the righteous and the unrighteous. Most call this collection of eerie realms the Shadowfell. Terror, magic, mystery, and suspense fill these fractured domains, an infinite gallery of unfolding evils, age-old plots, cursed bloodlines, legendary monsters, and immortal villains.
The most evil of evils from countless worlds regard the Shadowfell as their prison -- infamous figures such as the lich-king Azalin Rex, the corrupted wanderer known as The Crooked Mask, and, the most notable, the diabolical first vampire Strahd von Zarovich. These Darklords have wielded incredible power within their isolated domains, yet have been held captive in eternal torment as victims of malign forces known as the Dark Powers.
But something has changed. The lands have shifted. The Mists have opened. Domains of Dread once thought of as their own distant dimensions have closed in on one another, creating a new land within the Shadowfell, that scholars in the land have dubbed Tenebris.
Bluetspur, the domain of alien memories; The Carnival, the wandering domain of wonders; Dementlieu, the domain of decadent delusion; the nations of Barovia, the Burach Empire, the Chameault Kingdom -- all of it have coalesced into one domain. And at the center of it all, rises the Castle of Memories, the throne of the Raven Queen.

Introduction

However, your character possesses none of this information. After all, I cannot instill fear and suspense if you already possess the answers. In fact, you may never truly discover the entire story that is unfolding behind the scenes of Tenebris.
Welcome to my third canonical campaign: Domina Tenebris (or The Lady of Darkness). This will be my first ever horror-themed campaign, and I hope that you all come to enjoy it!
In the rest of this article, I will cover expectations, character creation, and any other various bits of knowledge or lore you'll need in order to jump into this campaign.

Expectations

As I mentioned, this campaign will be horror-themed. Now, obviously I can't instill horror and fear in the same way a movie would (I can't rely on jumpscares. Instead, I will rely on emotions and ideas such as hopelessness, uncertainty, powerlessness, and tension in order to convey fear and darkness. There will be times where you will have to run, I will not cater to your level in combat at all times. That's not to say that at level 1, I'll throw a dragon at you, but what I am saying is that not everything will be for you to fight. I will say this again: in this campaign your options in encounters will shift between combat, social acts (diplomacy/intimidation), or running, and it will be your job to determine which of those is most viable. I will try to make this campaign fun and challenging, but I will not tell you the right answer or even the right path forward in every scenario.
So, to take this opportunity, here's a list of themes I know I will encorporate at some point in the campaign: body horror (gore, disease, torture), religious corruption, carnival horror (clowns), political corruption (different from political intrigue, since it'll be quite obvious to you who the bad guy is), and probably more. I will, however, stay away from horror themes that I personally believe cross a line. My job is to create a tense environment that is still fun, not just shock for shock value's sake.
I also don't want this to be a slug-fest through a goth fantasy ("because tonight will be the night--"), instead I will also encourage breaks in the tension; little moments of hope that will remind you and your characters what you're progressing the story for. Occasional humor is good, so don't shy away from it! Just please respect the atmosphere, because you as the player will be in charge of creating this horror experience just as much as I am.
That being said, you are encouraged to create a dark-fantasy character, one that would fit in well with a horror setting. You'll be trudging through the Shadowfell as the Raven Queen remakes it into her own image, so creating Fruitloops, the Valiant Unicorn Princess would not be a good fit. While I am encouraging some humor in roleplay as to occasionally break tension, please don't make a meme character.
Oh, and lastly, with a horror-themed setting, the intrigue of grimm-dark fantasy will be cut. It should be painfully obvious who the antagonists in each part of the story are. However, in the case of a disagreement, the party would be encouraged to take a vote as to their next steps, and then expected to go along with whatever was decided.
Recap:

• This campaign will be horror-themed.
• I will not coddle you, you will have to decide what the right path forward in encounters will be. Do you fight? Do you run? Do you engage in social antics? That will always be for you to decide.
• Help me with the tense atmosphere! Don't constantly mock the campaign, let it be dark sometimes.
• But don't forbid yourself from making jokes. I'm just saying, limit how much you interrupt with a sly quip.
• Make a dark-fantasy character that would fit in the Shadowfell.
• No grimm-dark intrigue!

Variant Rules

In this campaign, there will also be a few variant rules I'll be incorporating to help make this campaign unique. They are described below:
Influence Dice. While adventuring in Tethoris, the players and the DM each will have a pool of six-sided dice to draw upon in order to shift the fates in their favor. The player's dice are known as Hope Dice, while the DM's pool consists of Beast Dice.
At the start of the campaign, each pool will have a single d6, but events during the game can add or remove dice from either pool. Neither pool can exceed 6d6's. After each session, if one dice pool has at least two more dice than the other, then an extra d6 will be added to the pool with fewer dice to represent Tenebris trying to give false hope.
The dice in each pool can be spent to acivate a number of different abilities, which will be explained at the end of this section (and I'll keep a list at the table, too, so that everyone remembers).
During play, the number of dice in each pool is another factor for the players to consider when plotting their next course of action. For this reason, the DM's amount of Beast Dice will always be visible, as well as represented in-game through natural phenomena or NPC's.
Hope Dice: Your characters will be faced with a world of overwhelming odds, and in order to triumph, they must draw upon deep personal reservoirs of courage and will. If a player accurately and faithfully represents their character's bonds, flaws, or ideas in difficult circumstances, a Hope Die may be added to your pool, or if your character performs a great act of selfishness or heroism. Here are the various abilities you can use by spending Hope Dice on:

• Hasty Recovery. Spending one Hope Die during a short or long rest allows a player to remove a condition or one level of exhaustion. If the player needs to make a saving throw during that rest, such as for a disease or poison, they may roll the Hope Die and add that number to their saving throw.
• Inner Strength. A player may spend a Hope Die instead of a Hit Die to recover hit points during a short rest or to activate any other ability that requires spending a Hit Die.
• Final Push. Whenever a player fails a death save, they may spend 2 Hope Dice to reroll that save.
• I've Just the Thing. A player may spend any number of Hope Dice and roll them in order to immediately gain a single item with value equal to or less than twice the rolled total in gold pieces.
• Blaze of Glory. The party may spend all 6 Hope Dice to grant themselves superhuman strength and resilience for a single round. During that round, all party members have advantage on all rolls, resistance to all damage, and all damage they deal is doubled.

The Beast Dice: The Beast of Blight is a powerful supernatural entity that stalks the lands of Tenebris that is beyond full comprehension. Whenever a character takes an action that furthers the darkness in the world, or when the party encounters a particularly strong, evil, or frightening being, the Beast Pool may receive another die. Below are the various effects the DM can activate by spending Beast Dice.

• Bitter Disposition. The GM may spend one Beast Die in order to decrease the starting disposition of an NPC from friendly to indifferent, or from indifferent to hostile.
• Death Rattle. When a player is reduced to 0 hit points, the DM may spend one Beast Die and roll it. On a 5 or 6, that player immediately fails one death save.
• Outnumbered. The DM may spend any number of Beast Dice at the start of an encounter to increase the number of creatures facing the party. For each die spent, the DM may add an additional creature with CR no greater than half the party's level, rounded down..
• Affliction. By spending 4 Beast Dice, the forces of darkness cause a serious ailment to strike a party member. The DM chooses a curse or transformation that afflicts a character of their choice.
• The Beast. Should the pool ever reach 6 dice, the DM may spend all 6 dice in order to have the Beast of Blight manifest near the player's location. The effects of the Beast's presence are felt throughout the region and vary based on the closest region of Tenebris.

Neutral Abilities: Apart from abilities specific to Hope Dice or Beast Dice, there are a few that can be used by either Hope or Beast dice:

• Minor Fate. Roll one die and add the total to a single attack roll, ability check, or saving throw.
• Brutal Strike. Whenever a creature is hit by an attack roll, the attacker may spend 2 dice and inflict a condition on the target for one round. The condition may be bleeding, dazed, prone, or stunned.

Sanity Score. In this campaign, we'll be using an extra ability score called Sanity. Life in Tenebris is always testing the limits of your willpower and mental and emotional strength. A character with high sanity is level-headed in the face of incomprehensible circumstances, while a character with low sanity is unsteady, breaking easily when confronted with the many horrors that are beyond normal reason.
With the addition of the Sanity score, an extra '11' will be added to Kingston's array (in this campaign only). The Kingston's array for this campaign will be 17, 16, 15, 14, 12, 11, 10
The DM may ask characters to make Sanity checks in place of Intelligence checks to recall lore about the dark creatures that roam Tenebris, to decipher writings of a raving lunatic, to learn spells from tomes of forbidden lore, or overcoming the lingering effects of madness.
The DM may call for a Sanity Saving Throw when a character runs the risk of succumbing to madness or darkness of Tenebris, such as in the following situations:

• Seeing a manifestation of the Beast of Blight
• Making direct contact with the mind of a truly evil entity.
• Being subjected to spells that affect mental stability, such as the insanity option of the symbol spell.

A failed Sanity save might result in short-term, long-term, or in very specific scenarios, indefinite madness. Any time a character suffers from long-term or indefinite madness, their Sanity score is reduced by 1. A greater restoration spell can restore Sanity lost in this way.

Character Creation

You will be starting at level 1. Any published work or work included in Kingston's Field Notes is acceptable. Please don't take this horror campaign as an excuse to min-max. Because one of the ways to instill tension and fear that I'll be using is occasionally throwing really challenging encounters at you, if one of you is mega powerful, I will up the difficulty to match, thus making everyone else feel like they are contributing nothing.
Do, however, play a character that you will have fun with! I'm not saying purposefully make your character weak, I'm saying don't raise the ceiling too high.
As for what your character's background, you will not enter the Shadowfell until the very beginning of session 1. That being said, your background can generally include anything (within reason). Your character can even be from other planes like the Feywild or even Avalon, just as long as you end up on the plane of Cynthia by the beginning of the campaign.
We'll use Kingston's array, the variant rules described above, no extra feats (since I made it so that every background grants one now), and that should be it. Let me know if you have any questions!