Body Tint, Colouring and Marking
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.
Shadow Dragon Template
Only a true dragon can transform into a shadow dragon, and only if it is born in the Shadowfell or remains there for several years. A
Dracolich can't be turned into a shadow dragon, since it loses its draconic nature when it becomes undead.
When a dragon becomes a shadow dragon, it retains its statistics except as described below. The shadow dragon might retain or lose any or all of its lair actions or inherit new ones, as the DM sees fit.
Damage Resistances. The dragon has resistance to necrotic damage.
Skill Proficiency: Stealth. The dragon's proficiency bonus is doubled for its Dexterity (Stealth) checks.
Living Shadow. While in dim light or darkness,, the dragon has resistance to damage that isn't Force, Phychic, or Radiant.
Shadow Stealth. While in dim light or darkness, the dragon can take the Hide action as a bonus action.
Sunlight Sensitivity. While in sunlight, the dragon has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
New Action: Bite. If the dragon deals Acid, Cold, Fire, Lightning, or Poison damage with its bite, change that damage type to Necrotic.
New Action: Shadow Breath. Any damage-dealing breath weapon possessed by the dragon deals necrotic damage instead of its original damage type. A humanoid reduced to 0 hit points by this damage dies, and an undead
Shadow rises from its corpse and acts immediately after the dragon in the initiative count. The shadow is under the dragon's control.
Comments
Author's Notes
Original Article taken from DnD 5e Monster Manual by The Wizards of The Coast (WotC)