Shadow dragons are true dragons that were either born in the Shadowfell or transformed by years spent within its dismal confines. Some shadow dragons embrace the Shadowfell for its bleak landscapes and desolation. Others seek to return to the Material Plane, hungry to spread the darkness and evil of the Plane of Shadow.

Dark Portals. Portals to the Shadowfell manifest in forlorn places and the deep gloom of subterranean caverns. The dragons that lair in such places often discover these portals and find themselves transported to a new realm. Ancient dragons that sleep in their lairs for months or years at a time might find themselves spirited away, never knowing that a portal has formed without their knowledge as they dream.

Recast in Shadow. The transformation to a shadow dragon happens over a period of years, during which time a dragon’s scales lose their luster and fade to a charcoal hue. Its leathery wings become translucent, its eyes paling to pools of opalescent gray. Shadow dragons find sunlight abhorrent, and they are weaker in bright light than they are in darkness. Darkness makes the dragon fade to a spectral shadow of its former self.

The magical nature of dragons holds an attraction for the Shadowfell, which seems somehow to crave the might and majesty of these great reptiles. The Shadowfell also has a dispiriting effect on its denizens, such that the longer a creature remains on the plane, the more it accepts the plane’s malaise. As months and years pass for a dragon on the Shadowfell, it becomes aware of the transformation being wrought upon it, and yet can do nothing to prevent it.

Back in the World. A shadow dragon is so suffused with the power of the Shadowfell that even a return to the Material Plane can’t undo its transformation. Some shadow dragons attempt to lure other creatures from the mortal realm back to the Shadowfell to keep them company, at least until they tire of their guests and devour them. Others are happy to leave the Shadowfell behind forever, understanding that treasure and power are easier to come by in the Material Plane.

Black dragons dwell in swamps on the frayed edges of civilization. A black dragon’s lair is a dismal cave, grotto, or ruin that is at least partially flooded, providing pools where the dragon rests, and where its victims can ferment. The lair is littered with the acid-pitted bones of previous victims and the fly-ridden carcasses of fresh kills, watched over by crumbling statues. Centipedes, scorpions, and snakes infest the lair, which is filled with the stench of death and decay.

Lair Actions

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

Banish Light. Any nonmagical source of illumination within a 60-foot-radius sphere centered on the dragon is snuffed out, and any spell that creates light within that same area is dispelled.

Cloud of Swarming Insects. A cloud of swarming insects fills a 20-foot-radius sphere centered on a point the dragon chooses within 120 feet of it. The cloud spreads around corners and remains until the dragon dismisses it as an action, uses this lair action again, or dies. The cloud is lightly obscured. Any creature in the cloud when it appears must make on a DC 15 Constitution saving throw, taking 10 (3d6) piercing damage on a failed save, or half as much damage on a successful one. A creature that ends its turn in the cloud takes 10 (3d6) piercing damage.

Drowning Tide. Pools of water that the dragon can see within 120 feet of it surge outward in a grasping tide. Any creature on the ground within 20 feet of such a pool must succeed on a DC 15 Strength saving throw or be pulled up to 20 feet into the water and knocked prone.

Shroud of Darkness. Magical darkness spreads from a point the dragon chooses within 60 feet of it, filling a 15-foot-radius sphere until the dragon dismisses it as an action, uses this lair action again, or dies. The darkness spreads around corners. A creature with darkvision can’t see through this darkness, and nonmagical light can’t illuminate it. If any of the effect’s area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.

Regional Effects

The region containing a legendary black dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:

Brooding Despair. Creatures within 1 mile of the dragon’s lair that have an Intelligence score of 5 or higher feel forlorn and hopeless.

Dying Light. Light is diminished within 6 miles of the dragon’s lair, lightly obscuring the land in gloomy shadows.

Gloomy Portals. Some caves, caverns, pits, and other places of deep gloom within 1 mile of the dragon’s lair form portals to the Shadowfell, allowing creatures from that plane to dwell nearby.

If the dragon dies, vegetation remains as it has grown, but other effects fade over 1d10 days.