Brionac of the Cold Winds

Hypothermic Scales. Brionac is immune to both cold and fire damage. If he would receive either of the damage types, he instead restores hit points equal to the damage he would have taken.

Savagery. Upon being reduced to half of his total hit points, Brionac draws his ceremonial dagger and changes to his Savage Form. While in savage form, he gains an additional 20ft of movement speed and moves on all fours, granting him a climbing and swimming speed.

In Savage Form. Insatiable Bloodlust. Whenever Brionac deals damage to an enemy with his melee attacks, he gains temporary hit points equal to the damage he dealt. Temporary hit points generated by this effect can be stacked with other temporary hit points generated by this effect.

Permafreeze. Whenever Brionac deals cold damage to a creature, he reduces their movement speed by 10 feet until the end of his next turn. A creature can have their movement reduced multiple times by this effect

Spellcasting. Brionac is 3rd-level spellcaster. His spellcasting ability is intelligence (spell save DC 20, +10 to hit with spell attacks). Brionac has the following spells prepared:
Cantrips (at will): fire bolt, frostbite 
1st level (2 slots): ice knife
5th level (3/day): cone of cold, steel wind strike
6th level (2/day): wall of thorns, wall of ice

Conjure Lesser Golem (Recharge 3-6). As an action, Brionac can present his ceremonial dagger and summon a lesser ice or fire golem to do his bidding. The golem is aligned with Brionac and will do as he commands, they gain their own position in initiative.

Conjure Greater Golem (Recharge 6). As an action, Brionac can present his ceremonial dagger and summon a greater ice or fire golem to do his bidding. The golem is aligned with Brionac and will do as he commands, they gain their own position in initiative.

In Savage Form. Multiattack. Brionac preforms three attacks, with at least one of them being with his dagger, he may also move up to 20ft between his attacks.

Dagger. Melee Weapon Attack: +14 to hit, reach 5 ft., 1 target. Hit: 7 (1d4 + 5) slashing damage. 

Freezing Shot. Ranged Weapon Attack: +10 to hit, range 20/60 ft., 1 target. Hit: 12 (2d6 + 6) cold damage.

In Savage Form. Mangle. Melee Weapon Attack: +12 to hit, reach 5 ft., 1 target. Hit: 18 (3d8 + 6) piercing damage.

In Savage Form. Bite. Melee Weapon Attack: +15 to hit, reach 5 ft., 1 target. Hit: 13 (3d6 + 4) piercing damage

Dash. Brionac's movement speed is doubled until the end of the current round.

Disengage. Brionac can move outside of other creature's movement speed without provoking reactions.

Dodge. Brionac prepares to dodge, he has advantage on saving throws and other creatures have disadvantage on attacks rolls made against him until the end of his next turn.

In Savage Form. Quick Attack. Brionac makes one attack with his dagger.

Freezing Touch. When a creature attempts to leave Brionac's melee range, he can attempt to reach out and freeze them. The creature must succeed on a dex save against Brionac's spell save DC, if they fail, their movement drops to 0 as they become frozen to the ground they stand in.

In Savage Form. Feast (3/day). When another creature falls unconscious within 50ft of Brionac, he can expend a reaction to pounce to that creature and feast on them. The creature takes 2d8s of slashing damage, then Brionac has that amount of hit points restored.

Brionac can take one legendary action per round, and up to three times per day.

Legendary Resistance (Costs 1 Actions). When Brionac would fail a saving throw, he can instead choose to succeed.