Legendary Resistance (3/Day): If Yamata no Orochi fails a saving throw, it can choose to succeed instead.

Magic Resistance: Yamata no Orochi has advantage on saving throws against spells and other magical effects.

Amphibious: Yamata no Orochi can breathe air and water.

Multiattack: Yamata no Orochi can use its Frightful Presence. It then makes eight attacks: combos between bite and tail

Bite: Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 7) piercing damage.

Tail: Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 15 (2d6 + 7) bludgeoning damage. If the target is a creature, it must succeed on a DC 21 Strength saving throw or be knocked prone.

Frightful Presence: Each creature of Yamata no Orochi's choice within 120 feet of it and aware of it must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to Yamata no Orochi's Frightful Presence for the next 24 hours.

Swallow: Yamata no Orochi makes one bite attack against a Large or smaller creature it is grappling. If the attack hits, the target takes the bite's damage, the target is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside Yamata no Orochi, and it takes 35 (10d6) acid damage at the start of each of Yamata no Orochi's turns. If Yamata no Orochi takes 60 damage or more on a single turn from a creature inside it, Yamata no Orochi must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate the swallowed creature, which falls prone in a space within 10 feet of Yamata no Orochi. If Yamata no Orochi dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Constrict: Melee Weapon Attack: +13 to hit, reach 5 ft., one creature. Hit: 22 (3d10 + 7) bludgeoning damage, and the target is grappled (escape DC 21). Until this grapple ends, the target is restrained, and Yamata no Orochi can't constrict another target.

Reactive Bite: When a creature within 10 feet of Yamata no Orochi hits it with a melee attack, Yamata no Orochi can use its reaction to make a bite attack against that creature.

Tail Sweep: When a creature misses Yamata no Orochi with a melee attack, Yamata no Orochi can use its reaction to make a tail attack against that creature.

Yamata no Orochi 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. Yamata no Orochi regains spent legendary actions at the start of its turn.

• Crush (Legendary Action, Costs 2 Actions): Yamata no Orochi attempts to crush a creature it is grappling. The target must make a DC 21 Strength saving throw, taking 33 (6d10) bludgeoning damage on a failed save, or half as much damage on a successful one. If the target is reduced to 0 hit points by this damage, it is crushed into paste, instantly killed.
• Detect: Yamata no Orochi makes a Wisdom (Perception) check.
• Move: Yamata no Orochi moves up to its speed without provoking opportunity attacks.

Wrathful Roar (Mythical Action, 1/Day): Yamata no Orochi unleashes a deafening roar, striking fear into the hearts of its enemies. Each creature of Yamata no Orochi's choice within 60 feet of it and aware of it must succeed on a DC 21 Wisdom saving throw or become frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to Yamata no Orochi's Wrathful Roar for the next 24 hours.