Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Master of Dwarves. The dragon has advantage on all Charisma checks made against Dwarves.
Undead Nature. The dragon is considered an Undead creature, and does not require food, water, or sleep to survive.
Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 7 (2d6) necrotic damage.
Claw. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 15 (2d6 + 8) slashing damage.
Tail. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.
Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.
Fire Breath (Recharge 5–6). The dragon exhales fire in a 60-foot cone. Each creature in that area must make a DC 21 Dexterity saving throw, taking 63 (18d6) fire damage on a failed save, or half as much damage on a successful one.
Terrifying Breath (Recharge 5–6). The dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 21 Constitution saving throw, taking 40 (9d8) necrotic damage on a failed save, or half as much damage on a successful one. A creature who fails their save is frightened for 1 minute.
A creature frightened by this ability is also paralyzed. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the frightening effect of the dragon's Terrifying Breath for the next 24 hours.
The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.
Detect. The dragon makes a Wisdom (Perception) check.
Tail Attack. The dragon makes a tail attack.
Burrow Strike (Costs 2 Actions). The dragon burrows under the ground and surfaces under a creature to attack. Each creature in the dragon's area must make a DC 22 Dexterity saving throw, taking 14 (2d6+7) bludgeoning damage on a failed save and be knocked prone, or half as much damage on a successful one and remain standing.
Description
The odor of death surrounds the dragon, whose horns are now brittle with decay and whose bones protrude through its rotting skin. Its sharp teeth peer through gaping holes in its jaw, as the stench from its breath leaks out uncontained.