Avatar Kuruk

Amphibious. The Avatar can breathe air & water

Aggressive. As a bonus action, Avatar Kuruk can move up to its speed towards a hostile creature it can see.

Battle Synergy. While mounted Avatar Kuruk & his Sabertooth Polar Bear Dog can exchange initiative (no action required) at the top of the round. 

Last Stand (Mystic Trait; Recharges after a long or short rest). If Avatar Kuruk’s mount dies, he absorbs it’s essence of power into himself, energizing him the rest of the battle. He regains 126 hit points and now all lightning damage he inflicts deal maximum damage rather than a roll. He also gains resistance to piercing slashing and bludgeoning damage.

Spellcasting. Avatar Kuruk is a 20th-level spellcaster. Its spellcasting ability is 18 (spell save DC 17, +4 to hit with spell attacks). The Avatar has following Sorcerer spells prepared, requiring no material components:

(at will): detect magic, earthbind, feather fall, levitate 
3/day each: control weather, counterspell

Multiattack. The Avatar makes two glaive attacks.

Glaive. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 26 (3d10 + 9) slashing damage. 

Heaven Piercer. The Avatar shoves his Glaive forward creating a powerful gust of wind that pierces everything in its path. All creatures in a 200 foot long and five foot wide line must succeed on a 22 Constitution saving throw or take 39 (6d12) piercing damage.

Storm Hammer (Recharges 5-6). The Avatar points a finger at an area he can see within 300 feet of him. A colossal hammer of lightning crashes down from the heavens on that location. All creatures within a 30 foot radius from the point of impact must succeed in a DC 17 Dexterity Saving Throw or take 4d8 lighting damage and 4d8 bludgeoning damage or half as much on a successful save. This ability deals triple damage to objects & structures. 

Avatar Kuruk can take three Legendary Actions, choosing from the options below. Only one legendary action option can be at a time and only at the end of a creature’s turn. The Avatar regains spent legendary actions at the beginning of its turn. 

Storm Hammer (Costs 3 Actions). While mounted, the Avatar can recharge his Storm Hammer Ability and use it. 

Heavenly Stride (Costs 2 Actions). The Avatar causes his mount to use his charge action attack. 

Strike. The Avatar can make a single Glaive attack.

If the Avatar’s Mystic trait is active, he can use the abilities below as legendary actions. 

Swift Strike. The Avatar can make one Glaive attack and then move half of its movement.

Fury of the Fallen (Costs 2 Actions). The Avatar attempts to pierce a creature with righteous rage. He makes a Glaive attack, on hit, the creature takes the damage and is impaled and lifted up. Lightning is guided through its body dealing 36 (3d12) lightning damage. Then it is thrown prone.