Keen Hearing.  Yurishi has advantage on Wisdom (Perception) checks that rely on hearing.

Magic Weapons. Yurishi's attacks are magical.

Magic Resistance. Yurishi has advantage on saving throws against spells and other magical effects.

Trampling Charge. If  Yurishi moves at least 20 feet straight toward a creature and then hits it with a gore attack on the same turn, that target must succeed on a DC 23 Strength saving throw or be knocked prone. If the target is prone, Yurishi can make one stomp attack against it as a bonus action.

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

Multiattack. Yurishi can make four attacks: one with its bite, one with its gore, and two with its claws.

Bite. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 19 (5d8 + 10) poison damage and the target must make a DC 23 Constitution saving throw, taking 17 (4d6+10) poison damage on a failed save, or half as much damage on a successful one.

Tail. Melee Weapon Attack: +17 to hit, reach 20 ft., one target. Hit: 17 (4d8 +10) bludgeoning damage.

Claw. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 22 (4d6 + 10) posion damage.

Gore. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 21 (4d10 + 10) acid damage and the target must make a DC 23 Constitution saving throw, taking 19 (4d8+10) acid damage on a failed save, or half as much damage on a successful one.

Stomp. Melee Weapon Attack: +17 to hit, reach 5 ft., one prone creature. Hit: 23 (5d12 + 10) bludgeoning damage.

Yurishi can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and the end of another creature's turn. Yurishi regains legendary actions at the start of its turn.

Tail Attack.  Yurishi makes a tail attack.

Frightful Presence. Each creature of  Yurishi's choice that is within 120 feet of Yurishi and aware of it must succeed on a DC 23 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each turn, ending the effect on itself on a success. If a creature's saving throw succeeds or the effect ends, the creature is immune to  Yurishi's Frightful Presence for the next 24 hours.

Poison Breath (Costs 2 Actions). Yurishi exhales poisonous gas in a 90-­‐foot cone. Each creature in that area must make a DC 23 Constitution saving throw, taking 77 (22d8) poison damage on a failed save, or half as much damage on a successful one.