Unique Biology. Baston T'sarr has advantage on saving throws against being charmed, and magic can’t put Baston T'sarr to sleep. Baston T'sarr can breathe without air.

Legendary Resistance (2/Day). If Baston T'sarr fails a saving throw, he can choose to succeed instead.

Transformation. If Baston T'sarr drops to 0 hit points, erupts in a demonic yet otherworldly light, briefly disappearing before instantly reappearing in his forth form, in an unoccupied space within 60 feet of where his third form disappeared. His initiative count doesn't change. Alternatively Baston T'sarr can as an action, activate this feature prematurely, if activated in this way he remains in his current space.

Innate Spellcasting (Psionics). Baston T'sarr’s innate spellcasting ability is Intelligence (spell save DC 18). He can innately cast the following spells, requiring no components:

At Will: destructive wave, blur

3/day each: divination, shield, haste (self only)

Multiattack. Baston T'sarr can make 4 attacks: 3 with his fists and 1 with his tail. Alternatively one of these attacks can be replaced with a claw attack.

Fist. Melee weapon attack: +10 to hit, reach 5ft., one target. Hit: 12 (2d6 + 4) Bludgeoning damage.

Claw. Melee weapon attack: +10 to hit, reach 5ft., one target. Hit: 12 (2d6 + 4) Slashing damage.

Tail. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage.

Baston T'sarr 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 dragon regains spent legendary actions at the start of its turn.

Tail Attack. Baston T'sarr makes a tail attack.

Telekinetic Fling. Baston T'sarr chooses a Small or smaller object that isn’t being worn or carried that he can see within 60 feet of it, and he magically hurls the object at a creature he can see within 60 feet of the object. The target must succeed on a DC 18 Dexterity saving throw or take 14 (4d6) bludgeoning damage.

Death Ray Barrage (2 actions). Ranged Spell Attack: +8 to hit, up to four targets, on a hit the creature(s) must succeed on a DC 18 Dexterity saving throw or take 22 (4d10) necrotic damage, half as much on a success.