Tranquility's End
Long ago, an autumn eladrin who's name has been long forgotten travelled from the feywild to the small community of Tranquility. He and his entourage of disguised centaur and satyr were sent by their Archfey patron to help rid the villagers of a terrible monstrosity that had befallen their lands, feasting on their livestock, spoiling their crops and picking off their farmers. The Archfey's ulterior agenda to bolster their own followers went according to plan after his emissaries slew the creature plaguing Tranquility whose citizens fell in love with the charming hero and his patron in turn.

All seemed like a fairytale ending, till the jealousy of the town's mayor, Eli van Hassen, had the eladrin and his entourage framed for heinous crimes against the mayor's daughter. The townsfolk quickly turned from adoring fans to angry mob and somehow subdued the fey, murdering the entourage where they fled and executing the eladrin by public beheading in the middle of the crossroads of the mayor's estate. The Archfey patron had already sworn vengeance against all involved and their families for generations to come before the eladrin's head had even come to a stop under a nearby rosebush. At the orders of Eli van Hassen, the mob dumped his body off the nearby bridge and into the running water below. His body floated downstream for hours, coming to rest under a yellow maple tree on the bank of a gentle curve in the river near a covered bridge, miles away from the van Hessan estate. It was then, once the poor eladrin's body had found it's final resting place, that the Dark Powers of the Domains of Dread took notice and The Mists swept over the land.

The next morning, van Hassen, his daughter Tahlitha and many of the townsfolk present at the killings woke up in a land that was a grotesquely beautiful reflection of the surrounds they knew. But that wasn't all. The moment the lost citizens ventured out of their homes and onto the reflections of their own streets, they were greeted by the rolling peel of approaching hooves, like distant thunder before the storm. Those who stayed outside in the streets and on the roads were quickly confronted with the eladrin risen again, headless and seeking revenge. He decapitated his murderers one by, testing to see if their head can fit his own, finally hunting down the mayor at the estate's manor, a magnificent and lavish reflection of the original on the Material Plane. However, the gates of the van Hassen estate mysteriously keep him at bay. To this day, he waits till the mayor and his people leave the grounds when he can finally take his final head and rest in peace.

The Horseman and his entourage of undead centaur and satyr are forces of nature of the Endless Road. They appear almost anywhere and at any time, demonstrating no motivation other than slaughter and revenge on the bloodline of those who unjustly murdered him, whether they be on the Material Plane, the Feywild or the Domain of Dread. None are innocent as per the curse of the Endless Road. Strangers who stumble through the bleed between the realms, drawn in by the mists on purpose or find themselves on the road at the wrong time could also find themselves fair game for the Horseman's axe. 

The Endless Road
To the average adventurer, he appears seemingly at random, when in actual fact he can sense anyone travelling the Endless Road and chooses his quarry precisely. Sometimes he attacks instantly; at other times he harries foes for hours, letting them escape so that he might ride them down once more. He most frequently appears where the road is wide, or where numerous paths converge, allowing him a wide field of battle. Those who try to flee the Endless Road are either run down by the Horseman or find themselves on a never ending, featureless highway, lined with dense forest and repeating the same twists, turns and straights until they perish, go mad or turn back.

The Horseman’s arrival is heralded by a sudden clouding of the sky, a moaning wind, a swirling of autumnal leaves and a damp, rising mist until little of the world beyond the road is visible. Day or night, the light that shines through the clouds takes on the sickly blue of the moon.

The Horseman appears amid thundering hooves atop a stead the locals have dubbed Spitfire. A headless apparition in a white soldier's uniform and red coat with gold embellishments fanning out above a stead of spitting flames, scorched flesh and exposed decaying bone. He stands in a saddle of blackest leather, one hand brandishing a blood-stained axe, it's unimaginably sharp edge gleaming in the moonlight above. The other hand holds aloft a flaming pumpkin head, booming a bloodcurdling, maniacal cackle.

Bound to the Road
The Headless Horseman is a force of nature, a wave of slaughter crashing along the the winding Endless Road and any thoroughfare that branches from it. He can sense and track any being on the road, specifically knowing and hunting those directly linked by family, patronage or favour to his murderers. He does not attack anyone else, ignoring all that accompany his quarry, that is until they attack him or get in his way.

On the Material Plane and the Feywild, The Headless Horseman will track his quarry in the most direct line he can, leaping fences, navigating forests and streets and entering buildings. However, in the Domain of Dread itself, he is solely bound to the road, unable leave it by any means. Riding his Nightmare companion, he can fly from the ground, but the force holding the Horseman at bay is still present above ground level. He can appear through the billow of mists or swirl of autumn leaves, stepping through like a gateway and can leave the same way he came. If he has found a head he is happy with though, he can only leave through the roofed bridge at either end of The Endless Road.

Additionally, any creature within 100 feet of the Headless Horseman also becomes bound to the road. When a creature tries to flee from the Horseman through the thick tangle of feywild trees, they emerge back onto the road on the opposite tree line at the end of their movement, regardless of the distance they chose to move.

Finally, the Headless Horseman cannot cross any body of water he himself could not jump (20 feet with a running start or 10 feet from stationary), even on the back of Spitfire. Therefore, the wooden roofed bridge at either "end" of the mapped, "known" area of The Endless Road becomes a barrier the Headless Horseman cannot cross. He can enter the bridge above the flowing river below, but he cannot step foot on the other side of the bank.

Curse of the Horseman
Any who have ties to the van Hassens or those who executed the Headless Horseman, either by blood, patronage or complicate employment or assistance, are marked for revenge for generations to come. Their descendants in either the Feywild or the Material Plane become the Headless Horseman's quarry. When they turn the same age the Horseman was at the time of his death, his appears amid a thunderstorm of hooves at the height of the next autumn season. Those who enter the derelict van Hassen estate in the Material Plane (even accidentally), those pluck the roses or grapes from in the reflection of the van Hassen gardens in the Feywild or those who strike a deal or favour with or take refuge with Eli van Hassen also become the Horseman's quarry also. The Headless Horseman comes for his quarry's heads either the following dusk, the moment they step foot on the Endless Road or at dusk on the birthday where they turn the same age as their descendant. 

Additionally, Tranquility and The Endless Road will not be rid of the curse of The Headless Horseman till he finally takes the head of Eli van Hassen or his own head is found under the rose garden in the van Hassen mansion grounds and reunited with with his own body at the other end of the 'known' part of The Endless Road under the roofed bridge and next to the ever yellow maple. The horseman will, of course, try to thwart and attempt to reunite head to body, because he wants to take van Hessan's head himself. If the Headless Horseman is slain, his body slowly crumbles into a cloud of orange embers, red rose petals and yellow maple leaves, like charred remains drifting away on a breeze. He then rises again the next dawn at the site of his grave on the plane of existence he last died.

The Domain of Dread called The Endless Road seems literally to have no end. While some travellers find themselves eventually returned to paths in the real world, or other regions of the Autumn Court, most who trod the Endless Road never reach any destination at all. They may walk until all traces of habitation or civilisation are lost behind them and find nothing but woods or hills to either side. The highway stretches and stretches before them leaving no choice but to perish on the road, go mad trying or turn around and go back.

Lair Actions

On initiative count 20 (losing initiative ties), the Headless Horseman takes a lair action to cause one of the following effects; the Headless Horseman can’t use the same effect two rounds in a row:

• 1d4+1 giant rose bushes or rose covered obelisks burst through the surface of the Endless Road from underneath the creatures of The Headless Horseman's choosing within 60ft of him. Creatures can make a Dexterity saving throw DC18 to avoid the eruptions, taking 3d6 piercing damage on a failed save or half as much on a success. Each time a hostile creature to the Headless Horseman starts its turn within 10ft or moves within 10ft of a rose bush or obelisk, it lashes out at that creature who can make a Dexterity saving throw DC18, taking 3d6 piercing damage on a failed save or half as much on a success. A rose bush or obelisk occupies a 10ft space, has a AC12, 10hp, immunity to poison and psychic damage, immunity to the blinded, deafened, frightened, paralyzed, poisoned and prone conditions and vulnerability to fire and cold damage. No more than four rose bushes or obelisks can be on the battlefields.
• A strong gale crashes down the Endless Road at the Horseman's back as though he had cast the gust of wind spell of DC18, but as wide as the current stretch of road. If a creature fails it's saving throw by 5 or more, it is knocked prone in addition to being pushed back 15ft. The wind lasts until the initiative count of 20 on the next round.
• Pumpkin creepers rapidly crawl in from the surrounding forest, reaching 20 ft from either edge of the road. Creatures hostile to The Headless Horseman who are in the area of pumpkin creepers must make a DC18 Strength saving throw or become restrained. A restrained creature can make the save again at the end of their turn. The area affected by the pumpkin creepers is considered difficult terrain.
• A natural fog rolls in from the tree line as though the fog cloud spell had been cast. The fog lasts until initiative count 20 on the next round.

Regional Effects

The Endless Road spans across the Material Plane, the Feywild and the Domain of Dread of The Endless Road itself, crossing over at the wood roofed bridge at "either end" of the Domain of Dread and outside the sleepy village of Tranquility in both the Material Plane and the Feywild. In all planes, this is the location where the Headless Horseman's body came to rest after being dumped in the river. The known and mapped stretch of road between the two bridges of the The Endless Road is a reflection of the very centre Autumnal Court's Kings Highway in the Feywild, unbeknownst to the inhabitants. It is also a reflection of the small stretch of road in the Material Plane around the small town of Tranquility and the long abandoned van Hassen estate. In the 150 miles around the area (only in Autumn in the Material Plane), one or more of the following effects:

• The Headless Horseman is aware of any creature, their location and the distance to them while they are on the road.
• The area is in a perpetual state of autumn; the trees are in autumnal colour, the sky is often cloudy and usually only parts when the moon is at its zenith, a light mist covers the ground at night and a cold breeze is often blowing through the forest.
• Wild pumpkin grow and spread virulently, getting abnormally large in most cases. They develop natural Jack'o'Lantern smiles that are always looking in the direction of any passersby, acting as the eyes and ears of The Endless Road and The Headless Horseman.
• Once a creature submits to feeling lost, lonely or without hope, the Endless Road teleports them to the nearest bend in the road from the nearest settlement, unbeknownst to the creature. Even if they've been travelling for hours or days, the moment they feel lost and want to return, safety is mere minutes away, the scent of hearth fire on the breeze and the sounds of civilisation in the air.

If the Headless Horseman beheads Eli van Hassen or his own head is reunited with his body, these effects fade over the course of 1d12 days or the Domain of Dread collapses.