According to legend, beneath the trappings of reality, there lies another world, invisible and untouchable to mortals, known as the Stygian Realm. It is a cold, shadowy place, where darkness reigns and the spirits of the unholy and unworthy wallow in torment and despair as they're dragged to oblivion by the mighty currents of a freezing river of inky blackness. In truth, the Stygian is an ocean. An endless sea of darkness that absorbs all sound, warmth, and light, and drains the life from any living thing unfortunate enough to feel the touch of its cold, brackish waters.

Most know of the Stygian through the work of necromancers and death priests, magicians and clerics who channel its power in an attempt to master the forces of life and death. However, there are others capable of harnessing the power of this world: an order of assassins known as the Stygian Nightblades.

By drinking and immersing themselves in the Stygian's waters, the nightblades gain the ability to turn any nearby shadow into a portal to the dark realm. They swim through reality as living shadows, unseen, unheard, and completely untouchable until they strike. They dip their weapons into its icy, life-stealing waters, allowing them to drain away their energy until they seemingly die from exhaustion. It's said that the strongest nightblades can call upon the Stygian's coldest waters, which are said to be so cold, they burn.

Today, the order as vanished, becoming the stuff of myth and legend. Some say it was wiped out by the church of the gods of light. Others say the power of the Stygian became too great for them and they drowned in the umbral sea. Still more believe that the order never vanished at all. That they're simply hiding. Lurking in the shadows. Bubbling beneath the surface, waiting to strike.

Just like they always have.

 

So, What About You?
Why did you become a Stygian Nightblade? How did you acquire the power of the shadowy waters beneath the realm of light? Who or what gave you this power? And what do you plan to do with it now that it's yours?

Perhaps you were inducted into the order, like many others? Maybe you're a rogue agent who grew a conscience or decided that you no longer wished to follow their rules? Maybe a surviving nightblade took you on as an apprentice to recruit you or just pass on their knowledge? Perhaps you stumbled upon a nightblade's weapon or similar artifact and accidentally opened a portal to the Stygian while fiddling around with it? Or maybe a rift opened up and you just happened to be at the wrong place at the wrong time?

Regardless of the circumstances, you now wield the power of the world's shadowy undercurrent. Will you use it to snuff out the flames of corruption or the light of righteousness?

The choice is yours.

 

Umbral Power

Starting at 3 level, you gain a connection to the shadowy power of the Stygian, represented by a pool of Umbral Dice, which are d6s. You have a number of these dice equal to twice your proficiency bonus, which you can expend to perform a variety of supernatural feats, as listed below. You regain all your Umbral Dice when you finish a long rest.

When you reach certain levels in this class, the size of your Umbral Dice increases: at 5 level (d8), 11 level (d10), and 17 level (d12). You can expend Umbral Dice to use the following powers:

Chill of the Night. As a bonus action, you may expend an Umbral Die to dip your weapons or up to 30 pieces of ammunition into a shadow, coating them the Stygian’s freezing waters. Your next attack inflicts an additional 1d6 cold damage equal and forces the target to make a Constitution save (DC equal to 8 + your proficiency bonus + your Dexterity modifier) or be blinded, deafened, or poisoned (chosen when you make the attack roll) for a number of rounds equal to the result of the Umbral Die.

At 9 the cold damage increases to 2d6 and you may choose to inflict vulnerability to either fire or radiant damage. At 17 level, the cold damage inflicted increases to 3d6 and you may expend two Umbral Dice to inflict one level of exhaustion (you still roll one to determine duration though).

Shadowy Guile. You call upon your dark powers to grant you aid. When you fail a Dexterity or Wisdom check, you may spend one Umbral Die and add the result to your roll to the check. You only expend the die if the roll succeeds.

Exhaustion levels gained by Stygian Nightblade abilities may stack up to your proficiency bonus.

Stygian Rift

You can tear open a portal to the Stygian as a bonus action. You may use this ability in the following ways:

Stygian Dive. You dive into the Stygian, allowing you to swim through reality. While diving, you gain a Swim speed equal to your movement speed and appear as a shadow moving along the floor. While submerged, you have advantage on Stealth checks in areas of dim light or darkness and nothing on the Material Plane can interact with or affect you, nor you affect or interact with the Material Plane. You can stay submerged for a number of minutes equal to your proficiency bonus or until you choose to end the ability as an action. Once these minutes are up, you’re cast out of the Stygian and back to reality. If the space you would normally appear in is occupied, you appear in the nearest available empty space.

Stygian Plunge. You may open a portal to the Stygian under your enemies’ feet, plunging them into the frigid, umbral waters. The target creature is forced to make a Dexterity save (DC equal to 8 +your Proficiency bonus + your Dexterity modifier). If the save fails, the target is plunged into the Stygian for a number of rounds equal to your proficiency bonus. If the target ends their turn while submerged in the Stygian, they take cold damage and must make a Constitution save (DC equal to 8 + your proficiency bonus + your Dexterity modifier) or be inflicted with a condition as per your Chill of the Night feature. As an action, the target may make a Strength check (DC equal to 8 + your proficiency bonus) to escape from the Stygian, emerging in an adjacent square. If there are no unoccupied spaces, the target cannot escape.

Stygian Current. Instead of trapping your victim in a static pool, you can shove them into one of the Stygian’s shadowy currents. The target creature is forced to make a Dexterity save (DC equal to 8 +your Proficiency bonus + your Dexterity modifier). If they fail, they fall into the Stygian and are whisked away by the currents in a straight line up to a number of feet equal to 10 times your proficiency bonus, or until they hit a wall or similar obstruction. Targets whisked away are allowed to make a Strength save every 10 feet to escape. If the save fails, they take cold damage, must make a Constitution save (DC equal to 8 + your proficiency bonus) or be inflicted with a condition as per your Chill of the Night feature, and continue being whisked away.

You may only use Stygian Plunge and Stygian Current on a target up to one size category larger than you. Once you use this feature, you can’t do so again until after you’ve completed a long rest or you spend an Umbral Die to use this feature again.

Stygian Resilience

Your connection to the Stygian has grown, inoculating you to its cold, draining effects. You gain Cold Resistance and have advantage on saving throws against blindness, deafness, poisoned, and exhaustion.

Draught of Absence

Your body has adapted to the Stygian waters enough that drinking them grants power. As a bonus action, you may drink the Stygian waters, changing you into an embodiment of darkness’ emptiness. You gain one of the following effects:

Absence of Warmth. You and all allies within 20 ft. gain Fire Resistance for 1 hour.

Absence of Sound. You create an area of magic silence as per the effects of the spell Silence for 10 minutes.

Absence of Light. You and all allies within 20 ft. become invisible and are immune to radiant damage for 1 hour or until dismissed.

Once you use this ability, you can’t do so again until you’ve completed a long rest of you spend an Umbral Die to use this feature again.

Darkest Waters

Your connection to the Stygian has reached its peak, allowing you to harness the power of its deepest, darkest, coldest depths. When you use your Chill of the Night, Stygian Plunge, or Stygian Current features, you may apply one of the following effects:

Phlegethon. The icy chill of the so cold, it burns. Your features do not inflict conditions, but your cold damage is treated as fire damage for the purpose of resistance, vulnerability, and immunity.

Acheron. You bring the life sapping properties of the Stygian waters are brought to their full power. You double the result of your Umbral Die when determining the duration of conditions.

Cocytus. You entrap your victims in umbral ice, leaving them trapped and brittle. Your features may inflict paralysis on your targets.

Once you use this feature, you can’t do so again until after you’ve completed a long rest or you spend three Umbral Dice to use this feature again.