Amatsumagatsuchi

Legendary Resistance (2/Day). If the amatsu fails a saving throw, it can choose to succeed instead.

Wind Barrier. A barrier of strong wind surrounds the amatsu in a 10-foot radius around it. The strong wind keeps fog, smoke, and other gases at bay. Small or smaller flying creatures or objects can't pass through the barrier. Loose, lightweight materials brought into the barrier fly upward. Arrows, bolts, and other ordinary projectiles launched at the amatsu are deflected upward and automatically miss. (Magic arrows, boulders hurled by Giants or siege engines, and similar projectiles, are unaffected.) Creatures in Gaseous Form can't pass through the barrier.

Suppressed Power. The amatsu is unable to use its Grand Vortex Beam while it is above half of its maximum hit points (90).

Multiattack. The amatsu makes one Tail attack and one Bite attack. It can replace any of these attacks with a Water Beam attack.

Bite. Melee Weapon Attack. +12 to hit, reach 15 ft., one target. Hit: 19 (3d8 + 6) piercing damage.

Tail. Melee Weapon Attack. +12 to hit, reach 20 ft., one target. Hit: 28 (4d10 + 6) bludgeoning damage, and the target must make a DC 20 Strength saving throw or be knocked prone.

Water Beam. Ranged Weapon Attack. +6 to hit, reach 150/600 ft., one target. Hit: 23 (5d8) acid damage.

Wind Vortex (Recharge 5-6). The amatsu conjures a swirling vortex of hurricane winds centered on itself. Each creature within 100 feet of the amatsu must make a DC 20 Strength saving throw or be pulled 30 feet towards the amatsu. A creature that is pulled within 30 feet of the amatsu or is already within that range must make a DC 20 Strength saving throw or be thrown 130 feet straight up into the air on a failed save, or half as high on successful one. If a thrown target strikes a solid surface upon landing, the target takes 3 (1d6) bludgeoning damage for every 10 feet it fell.

Grand Vortex Beam (Recharge 6). The amatsu exhales three high pressure beams of water in different directions in front of it. Each beam is a 60-foot line that is 5 feet wide. Each creature in a line must make a DC 20 Dexterity saving throw, taking 82 (15d10) acid damage on a failed save, or half as much damage on a successful one.

Control Weather (1/day). The amatsu can alter the weather in a 6-mile radius centered on it. The amatsu doesn't need to be outdoors; otherwise the effect is identical to the control weather spell.

The amatsu 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 amatsu regains spent legendary actions at the start of its turn.

Bite Attack. The amatsu makes a bite attack.

Detect. The amatsu makes a Wisdom (Perception) Check.

Whirlwind (Costs 3 Actions). The amatsu chooses 3 unoccupied 5-foot cubes within 5 feet of it. An elemental force that resembles a dust devil appears in the cubes and move in a straight line 60 feet away from the amatsu before dispersing. Each creature in a lines must make a DC 20 Strength saving throw, taking 18 (4d8) thunder damage on a failed save or half as much damage on a successful one.