Flame sphere. Each creature that starts its turn within 5 ft of the zythar takes 10 (2d10) fire damage. 

Evasive haze. Ranged attacks have disadvantage against the zythar. 

Curse of the balor. The zythar on being reduced to 0 hit points explodes into flame and each creature must make a dc 19 Constitution save or take 35 (7d10) fire damage on a failed save, half damage on a successful one and if any ignitable items not worm or carried are in the area they are destroyed. 

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

Magic Weapons. The zythar’s weapon attacks are magical.

Multi attack. The zythar makes one fiery slam, one flame bolt and one tendrils of flame attack. 

Fiery slam. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: 6 (2d6) [bludgeoning] damage plus 6 (2d6) fire damage. 

Flame bolt. RangedWeapon Attack: +9 to hit, range 15/50 ft., 1 target. Hit: 24 (5d6 + 9)[fire] damage.

Tendrils of flame. One creature that the zythar can see within 100 ft must make a dc 19 Dexterity saving throw or take 27 (6d6 + 9) fire damage and gain a vulnerability to fire damage until the end of the zythar's next turn. On a successful save they take half damage. 

Abyssal flameburst (Once per long rest). Each creature within a a 50 ft radius must make a dc 19 Constitution saving throw or take 25 (5d10) fire damage and are blinded for 1 minute. The targets can remake the save at the end of their turn, on a successful save they take half damage.