Always Watching. The elder dragon has advantage on Wisdom (Perception) checks.

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

Multiattack. The elder dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 7 (2d6) psychic damage.

Claw. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 15 (2d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.

Frightful Presence. Each creature of the elder dragon's choice that is within 120 feet of the elder dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the elder dragon's Frightful Presence for the next 24 hours.

Psychic Blast (Recharge 5–6). The elder dragon exhales purple flames in a 60-foot cone. Each creature in that area must make a DC 19 Wisdom saving throw, taking 63 (18d6) psychic damage on a failed save, or half as much damage on a successful one.

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

Detect. The elder dragon makes a Wisdom (Perception) check.

Tail Attack. The elder dragon makes a tail attack.

Psychic Beams (Costs 2 Actions). The elder dragon roars and each of its eyes on its body open, shooting out purple beams. Each creature within 10 feet of the elder dragon must succeed on a DC 22 Dexterity saving throw or take 15 (2d6 + 8) psychic damage and be paralyzed until the end of its next turn.