Death Throes. The zythar explodes when it dies. Dexterity Saving Throw: DC 19, each creature in a 20-foot Emanation originating from the zythar. Failure: 21 (6d6) Fire damage plus 21 (6d6) Force damage. Success: Half damage. Failure or Success: If the zythar dies outside the Abyss, it gains a new body instantly, reviving with all its Hit Points somewhere in the Abyss.

Fire Aura. At the end of each of the zythar's turns, each creature of the zythar's choice in a 5-foot Emanation originating from the zythar takes 10 (3d6) Fire damage unless the zythar has the Incapacitated condition.

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

Magic Resistance. The zythar has Advantage on saving throws against spells and other magical effects.

Multiattack. The zythar uses Flame Tendril and makes one Fire Burst attack.

Fire Burst. Melee or Ranged Attack Roll: +11, reach 5 ft. or range 60 ft. Hit: 17 (3d6 + 7) Fire damage.

Flame Tendril. Dexterity Saving Throw: DC 19, one creature within 90 ft. Failure: 21 (4d6 + 7) Force damage plus 10 (3d6) Fire damage. Success: Half damage.

Firewall (Recharge 4-6). The zythar casts Wall of Fire without requiring Material components, using Charisma as the spellcasting ability (spell save DC 12).

Teleport. The zythar teleports up to 20 feet to an unoccupied space the zythar can see.