Agyra

Electrified Corpse. If Agyra is slain, her corpse crackles and flashes with pulses of electrical light. Any creature that touches her corpse takes 3d6 points of lightning damage. Even if Agyra’s body is destroyed, the site of her death continues to carry this electrical charge for 1 minute, or until Agyra is reborn, whichever comes first.

Rebirth. Agyra remains dead for only 1 minute before she come back to life, as if via a true resurrection spell. Agyra rises from the exact same position she occupied when she died, and typically takes advantage of this second chance to use her swift flight to escape as soon as possible. Agyra can only be reborn in this manner once per year; if she is slain a second time before a year has passed, her death is permanent and her corpse does not become electrified.

Flyby. The Agyra doesn’t provoke an opportunity attack when it flies out of an enemy’s reach.

Thunderous Blast. When Agyra uses her swift flight, she creates a thunderous sonic boom. This devastating explosion of thunder occurs at her location when she activates swift flight, filling an area equal to her space and her reach combined—resulting in a 100-foot-diameter burst of sonic energy. All creatures in this area of effect take 20d10 points of thunder damage, are deafened, are knocked prone, and are stunned for 1 round unless they succeed on the save. A successful DC 22 Constitution save halves the damage, the creature isn't deafened, the creature isn't knocked prone, and it doesn't become stunned. 

Siege Monster. Agyra deals double damage to objects and structure.

Regeneration. Agyra regains 15 hit points at the start of its turn if it has at least 1 hit point.

Legendary Resistance (3/day). If Agyra fails a saving throw, it can choose to succeed instead.

Magic Resistance. Agyra has advantage on saving throws against spells and other magical effects.

Frightful Presence. Each creature that is within 120 feet of Agyra and aware of it must succeed on a DC 25 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 a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Agyra's Frightful Presence for the next 24 hours. 

Multiattack. Agyra makes two bite melee attacks, two talon melee attacks and a tail slap melee attack.

Bite. Melee Attack. +17 to hit, reach 15ft, 6d6 + 8 Piercing.

Talon. Melee Attack. +17 to hit, reach 20ft, 3d8 +8 Piercing.

Tail Slap. Melee Attack. +17 to hit, reach 30ft, 8d6 + 8 Slashing. 

Blinding Flash. By spreading her wings as an action while she stands upon the ground, Agyra can create a blinding flash of light that targets all creatures within 100 feet. Affected creatures must succeed at a DC 22 Constitution save or be blinded and staggered for 1d6 rounds by the blast of light. 

Breath Weapon (recharge 5-6). As an action, each of Agyra’s twin heads can breathe out a line of lightning to a range of 1,200 feet. Agyra can breathe each line in a different direction. Each creature caught in a line of lightning must succeed at a DC 23 Dexterity save or take 20d6 points of lightning damage and be stunned for 1d4 rounds. A successful saving throw halves the damage and negates the stunning effect. A creature wearing metal armor or a creature composed mostly of metal that fails its saving throw is also paralyzed for 1 round. A creature slain by Agyra’s breath weapon remains electrified for 2d4 rounds after death—any creature that touches the body automatically takes 3d6 points of lightning damage.

Swift Flight. As an action once per hour, Agyra can fly in a straight line at an incredible speed. She may travel up to 1 mile in this manner—doing so does not provoke attacks of opportunity. When Agyra activates this ability, her thunderous blast ability is automatically triggered from the swift flight’s point of origin.

Agyra 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. Agyra regains spent legendary actions at the start of its turn.

Blinding Flash (Costs 2 Actions). Agyra uses its Blinding Flash action.

Tail Slap. Agyra makes one Tail Slap attack.

Whirlwind (Costs 2 Actions). Agyra casts whirlwind spell without using a spell slot or the required components.