Blue Dragon Alpha

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Colossal. The dragon's space is 30 ft by 30 ft, it has advantage on Strength (Athletics) checks versus huge or smaller creatures.

Shock. When a creature takes lightning damage from the dragon's attacks it seizes with energy. The creature takes 5 (1d10) lightning damage at the start of it's turn. A shocked creature can spend their action to remove the discharge.

Innate Spellcasting. The dragon's innate spellcasting ability is Charisma (Spell save DC 22, +14 to hit). It can innately cast the following spells, without material components:

At-will: Lightning Bolt, Lightning Lure (17th level), Shatter (Cast at 9th Level)

3/day each: Storm Sphere, Elemental Bane (Lightning)

1/day each: Chain Lightning, Illusory Dragon (Lightning)

Magic Resistance. The dragon has advantage on saving throws against spells and magical effects.

Magic Weapons. The dragon's attacks are considered magical for overcoming resistances.

Unstoppable. If the dragon is subject to an effect that would inflict the paralyzed, restrained, or stunned condition; it instead loses on legendary action, and its speed is reduced by half for the duration of the spell or effect. The lose of legendary actions is cumulative.

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: +17 to hit, reach 15 ft., one target. Hit: 37 (5d10 + 10) piercing damage plus 22 (4d10) lightning damage.

Claw. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 27 (5d6 + 10) slashing damage.

Tail Sweep. The dragon swings it's tail in a 40 ft. cone. The dragon makes an attack against every creature in the area. If hit a creature must make a DC 25 Strength or Dexterity saving throw, or be pushed 20 ft away and knocked prone 

Frightful Presence. Each creature of the dragon's choice that is within 240 feet of the dragon and aware of it must succeed on a DC 21 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.

Lightning Strike. Ranged Spell Attack : +14 to hit, range 480 ft., one target. Hit:  21 (6d6) lightning damage, and the target must make a DC 21 Constitution saving throw or lose any resistance to lightning damage for the next turn, and take an additional 21 (6d6) lightning damage.

Breath Weapon (Recharge 5–6). The dragon uses one of the following breath weapons. 

Lightning Breath . The dragon exhales lightning in a 150-foot cone. Each creature in that area must make a DC 22 Dexterity saving throw, taking 128 (24d10) lightning damage on a failed save, or half as much damage on a successful one.

Thunder Clap. The dragon roars, ending shock waves that can be felt from up to 300ft away. Each creature in the area must make a DC 22 Dexterity saving throw, taking 141 (26d10) lightning damage on a failed save, or half as much on a successful one.

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.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Aura Of Lightning (Costs 3 Actions). The dragon erupts in static energies that lash out in a 10-foot radius until the end of the dragons next turn.Any creature that starts or ends it's turn in the aura, or that hits the dragon with a melee attack takes 10 (3d6) lightning damage. In addition the dragon sheds bright light for 60 ft., and dim light for an additional 60 ft. The dragon also gains a +4 to AC against ranged attacks.