Arc Tempered Rey Dau

Berserk. If the Rey Dau takes 40 damage during turns other than its own, it screeches and grows enraged. Each turn while enraged, it can take a second action which can't be used on a multiattack. At the end of each turn, it rolls a D6. On a 1-5, it remains enraged. On a 6 it calms down.

Escape. If the Rey Dau falls to 80 hit points and has a flying speed, it flees the location and flies to the next closest safe location. If it has no flying speed, it becomes berserk.

Breakable Parts. When the Rey Dau takes sustained damage to a specific body part, that part might break off. If it does, they lose some mobility and attacks. If a part takes 40 damage within 1 turn, it becomes weak. If it takes 60 more damage before the Rey Dau begins it's turn, the part snaps off. The 4 parts are:
Horns - If the horns are destroyed, the Rey Dau loses the ability to use its Horn Strike or Focused Blast attack. To get the ability to use Focused Strike again, it must roll a 6 on the Recharge, in which it can use it. If it uses Focused Strike while its horns are broken, it loses the ability to recharge the attack.
Claws - If the claws are destroyed, the Rey Dau loses the ability to use its Claw Strike.
Wings - If the wings are destroyed, the Rey Dau’s fly speed slows down to 20. If the Rey Dau is in the air while its wings are broken, it plummets to the grab and falls prone. It must use an action to get up.
Tail - If the tail is broken, it slices off - leaving it lying on the ground. The Rey Dau can no longer use its Tail Swipe attack and slows down, dropping its flying speed to 30 ft. This instantly causes the Rey Dau to attempt to flee.

Multiattack. The Rey Dau makes three attacks between Horn Strike, Claw Strike, Wing Strike, and Tail Strike. It can not use the same attack more than once.

Horn Strike. Melee Attack Roll: +8, reach 5 ft. Hit: 21 (4d8 + 4) Piercing damage.

Claw Strike. Melee Attack Roll: +8, reach 5 ft. Hit: 21 (4d8 + 4) Slashing damage.

Tail Swipe. Melee Attack Roll: +8, reach 15 ft. Hit: 19 (4d8 + 2) Bludgeoning damage.

Wing Strike. The Rey Dau strikes a line in the ground 20 ft long. The Rey Dau makes a horn strike against each of them. Any creature within 5 ft of the line must make a Dexterity saving throw with a Difficulty Challenge of 16 or take 7d8 damage. They take no damage on a success.

Focused Blast (Recharge 3-6). The Rey Dau centers it's horns toward a single point and unleashes a beam of channeled electricity at a point it can see within 80 feet. Any creature within 5 ft of the point makes a 16 Dexterity saving throw. On a failed save, the target takes 10d8 lightning damage, or half as much on a success. Any creature in the line between the target and the Rey Dau must make a DC 16 Dexterity Saving Throw or be knock prone.

Aftershock. The Rey Dau chooses any target that can see it dealt damage to this turn. The target and any creature within 5 feet of it must make a DC 14 Constitution saving throw. If they fail, they take 4d8 lightning damage and become paralyzed until the end of their next turn. Otherwise, they take no damage.

Reactive Strike. If a target misses an attack against the Rey Dau, the Rey Dau may make a Horn Strike against that creature as a reaction.

Legendary Action Uses: 3. Immediately after another creature’s turn, the Rey Dau can expend a use to take one of the following actions. The Rey Dau regains all expended uses at the start of each of its turns.

Swift Bolt. Dexterity Saving Throw: DC 17, each creature in a 40-foot-long, 5-foot-wide Line. Failure: 11 (3d6) lightning damage, and the target is pushed up to 30 feet straight away from the dragon. Success: Half damage only. Failure or Success: The Rey Dau can’t take this action again until the start of its next turn.

Stride. The dragon moves up to half its Speed, and it makes one horn strike attack.

Disperse. The Rey Dau makes a contested atheletics check against a target that attacked it this turn. If it succeeds, the target becomes prone and the Rey Dau can fly up to 30 ft.