Magic Resistance. Zrin-Hala has advantage on saving throws against spells and other magical effects.

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

Living Storm. Zrin-Hala can enter a hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing. Creatures in Zrin-Hala's space take 9 (2d8) lightning damage at the start of their turn.

Wind Body. Ranged weapon attacks made against Zrin-Hala have disadvantage on the attack roll.

Spellcasting. Zrin-Hala is a spellcaster. Its spellcasting ability is Wisdom (spell save DC 20, +12 to hit with spell attacks). Zrin-Hala has following spells:
At will: lightning bolt, call lightning, thunder step, wind wall, ice storm, storm sphere, control winds
3/day: cone of cold, destructive wave, maelstrom, chain lightning, whirlwind
1/day: Tsunami. storm of vengeance

Multiattack. Zrin-Hala can use its Frightful Presence. It then makes three slam attacks.

Slam. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage and 18 (4d8) lightning damage.

Frightful Presence. Each creature of Zrin Hala's choice that is within 1 mile of Zrin-Hala and aware of it must succeed on a DC 22 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 Zrin-Hala's Frightful Presence for the next 24 hours.

Whirlwind (Recharge 4–6). Each creature in Zrin-Hala's space must make a DC 22 Strength saving throw. On a failure, a target takes 44 (9d8 + 4) bludgeoning damage and is flung up 40 feet away from the elemental in a random direction and knocked prone. If a thrown target strikes an object, such as a wall or floor, the target takes 7 (2d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 22 Dexterity saving throw or take the same damage and be knocked prone.

If the saving throw is successful, the target takes half the bludgeoning damage and isn't flung away or knocked prone.

Zrin-Hala 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. Zrin-Hala regains spent legendary actions at the start of its turn.

Slam. Zrin-Hala makes a slam attack.

Lightning Bolt. Zrin-Hala casts lightning bolt.

Thunder. A loud booming crack of thunder is heard. Each creature within 30 ft that can hear must make a DC 20 Constitution saving throw of become stunned until the end of Zrin-Hala's next turn. 

Eye of the Storm (Costs 2 actions). Each creature not within Zrin-Hala's space must succeed on a DC 22 Strength saving throw or take 40 (8d8 + 4) bludgeoning damage and be knocked prone. On a successful save, a creature takes half damage and is not knocked prone.