Armasar

Keen Sight. The griffon has advantage on Wisdom (Perception) checks that rely on sight.

Legendary Resistance (3/Day, or 4/Day in Lair). If the griffon fails a saving throw, it can choose to succeed instead.

Steady. The griffon has advantage on ability checks and saving throws against being knocked prone.

Multiattack. The griffon makes three Rend attacks.

Rend. Melee Attack Roll: +8, reach 5 ft. Hit: 13 (2d8 + 4) Piercing damage. If the target is a Medium or smaller creature, it has the Grappled condition (escape DC 16) from both of the griffon’s front claws.

Sonic Screach (Recharge 5-6). Wisdom Saving Throw: DC 16, each creature of its choice in a 30-foot radius who can hear it. Failure: The target has the Stunned condition until the end of the griffon's next turn. 

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature’s turn, the griffon can expend a use to take one of the following actions. The griffon regains all expended uses at the start of each of its turns.

Detect. The griffon makes a Wisdom (Perception) check.

Buffet. Strength Saving Throw: DC 16, each creature not grappled by the griffon in a 30-foot Cone. Failure: 5 (2d4) Bludgeoning damage, and the target is pushed up to 15 feet straight away from the griffon. Success: Half damage only. Failure or Success: The griffon can’t take this action again until the start of its next turn.

Charge. The griffon moves up to its Speed without provoking opportunity attacks and makes a Rend attack with advantage. If the attack hits, but is not a critical hit, the attack deals an extra 18 (4d8) radiant damage. The griffon can’t take this action again until the start of its next turn.