Aranoan Roc

Dive Attack. If the roc is flying and dives at least 30 feet straight toward a target and then hits it with a melee weapon attack, the attack deals an extra 36 (8d8) damage to the target.

Flyby. Any opportunity attack when the roc flies out of an enemy's reach is at disadvantage.

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

Multiattack. The roc makes three attacks. 

Beak. Melee Attack Roll: +15, reach 10 ft. Hit: 28 (3d12 + 9) Piercing damage.

Talons. Melee Attack Roll: +15, reach 5 ft. Hit: 23 (4d6 + 9) Slashing damage. If the target is a Huge or smaller creature, it has the Grappled condition (escape DC 19) from both talons, and it has the Restrained condition until the grapple ends.

Swoop (Recharge 5–6). The roc can make an additional Beak or Talon attack as a Bonus Action.

Incapacitating Screech. Once per turn, the Aranoan Roc may issue a mighty hunting cry as a bonus action, terrifying rivals and prey within earshot.

Any creature that can hear within 300 ft. of the Ancient Roc must pass a DC 18 WIS saving throw. On a failure, the creature is Frightened until the end of their next turn. If a creature fails the save by five or more, they are Incapacitated with fear until the beginning of their next turn.

Gusting Beat (Recharge 5–6). The roc beats its wings, creating a short, sudden, and strong rush of wind.  Each creature within a 60 foot cone of the roc must succeed on a DC 18 Dexterity saving throw or take 21 (6d6) force damage and be pushed back 10 feet.