Legendary Resistance (3/day). If Xixerion fails a saving throw, he can choose to succeed instead.

Multiattack. Xixerion makes 2 psychic dagger attacks. In replace of one of this attacks he uses his psychic choke.

Psychic Choke. One creature within 5 feet of Xixerion must make a DC 26 intelligence saving throw or become incapacitated for 1 minute. While incapacitated in this way the creature is grappled by Xixerion and takes 52 (4d12) psychic damage at the start of each of its turns. At the end of each of the creatures turns it can make a DC 26 intelligence saving throw, ending this effect on a success.

Psychic dagger. Melee Weapon Attack: +11 to hit, reach 5 ft., 1 target. Hit: 19 (4d6 + 5) psychic damage. 

Psychic blast (recharge 6). Ranged Weapon Attack: +16 to hit, range 60/120 ft., 1 target. Hit: 23 (2d12 + 10) psychic damage.

Arcane fazing. In return to being hit by an attack, Xixerion Fazes out of reality for a moment turning the hit into a miss. 

Fast movement. Xixerion can take the dash and disengage actions as a bonus action.  

Xixerion 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. Xixerion regains spent legendary actions at the start of its turn.

Psychic Gaze (costs 2 actions). One creature who can see Xixerion must make a DC 26 wisdom saving throw. On a failed save the creature becomes charmed for 1 round. while charmed in this way, the creature is incapacitated and has a speed of 0. The effect ends for the affected creature if it takes any damage or if someone else uses an action to shake the creature out of its stupor.

Arcane fazing (costs 3 actions). Xixerion increases his armor class by 5 for 1 round.