Undead Wyvern

Multiattack. The Undead Wyvern can use its Frightful Presence. It then makes three attacks: one with its bite and two with its back claws or one tail and one wing attack.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 5 (1d10) lightning damage.

Back Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.

Frightful Presence. Each creature of the Undead Wyvern's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 17 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 Undead Wyvern's Frightful Presence for the next 24 hours.

Wing Attack. The Undead Wyvern beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 20 Dexterity saving throw or take 14 (2d6 + 7) bludgeoning damage and be knocked prone. The Evolved Wyvern can then fly up to half its flying speed.

The Undead Wyvern 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 Undead Wyvern regains spent legendary actions at the start of its turn.

Slowing Breath. The Undead Wyvern exhales gas in a 60-foot cone. Each creature in that area must succeed on a DC 18 Constitution saving throw. On a failed save, the creature can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the creature can use either an action or a bonus action on its turn, but not both. These effects last for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself with a successful save.

Necrotic Breath (Costs 2 actions). The Undead Wyvern exhales lightning in a 90-­foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 66 (10d12) Necrotic damage on a failed save, or half as much damage on a successful one.