Balor Berserker. If Vivian is reduced to 120 hit points or fewer, Vivian enters his mythic state. Taking on much more of the balor's destructive energy. While in this state he has accses to his mythic actions and traits. Vivian also becomes size large Once Vivian goes berserk, he continues to do so until he is destroyed or regains all his hit points.

Fire Aura (Mythic Trait). At the start of each of Vivian's turns, each creature within 5 feet of him takes 10 (3d6) fire damage, and flammable objects in the aura that aren't being worn or carried ignite. A creature that touches the Vivian or hits him with a melee attack while within 5 feet of it takes 10 (3d6) fire damage.

Brute (Mythic Trait). A melee weapon deals one extra die of its damage when Vivian hits with it (included in the attack).

Immutable Form. Vivian is immune to any spell or effect that would alter his form.

Lightning Absorption. Whenever Vivian is subjected to lightning damage, he takes no damage and instead regains a number of hit points equal to the lightning damage dealt.

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

Magic Weapons. Vivian's weapon attacks are magical.

Assassinate. During its first turn, Vivian has advantage on attack rolls against any creature that hasn't taken a turn. Any hit the Vivian scores against a surprised creature is a critical hit.

Death Throes. When Vivian dies, it explodes, and each creature within 30 feet of it must make a DC 18 Dexterity saving throw, taking 35 (10d6) fire damage on a failed save, or half as much damage on a successful one. The explosion ignites flammable objects in that area that aren't being worn or carried, and it destroys Vivian's weapons.

Vivian 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. Vivian regains spent legendary actions at the start of her turn.

Attac. Vivian makes one attack with a weapon.

Teleport (Costs 2 Actions). Vivian magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.

Necrotic Shroud (Costs 3 Actions). Vivian causes other creatures within 10 feet of you that can see you must each succeed on a Charisma saving throw DC 18 or become frightened of you until the end of your next turn.

If Vivian's mythic trait is active, he can use the options below as legendary actions, as long as he is in his berserker state.

Thunderous Smite. Vivian makes an attack with his long sword. If it hits the creature, it takes an extra 7 (2d6) thunder damage and must succeed on a DC 18 Constitution saving throw or become stunned until the start of his next turn.

Hellfire Orb (Recharge 6 Costs 2 Actions). Vivian hurls a magical ball of fire that explodes at a point him can see within 120 feet of it. Each creature in a 20-foot-radius sphere centered on that point must make a DC 18 Dexterity saving throw. The sphere spreads around corners. A creature takes 24 (7d6) fire damage and 24 (7d6) necrotic damage on a failed save, or half as much damage on a successful one.