Avatar of Umberlee

Aquatic Nature: The Avatar can breathe air and water.

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

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

Multiattack. The Avatar can use its Fathomless Gaze and make three attacks: two with its Coral Trident and one with its Tail.

Coral Trident. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 32 (4d10 + 10) piercing damage plus 18 (4d8) lightning damage.

Tail. Melee Weapon Attack: +18 to hit, reach 20 ft., one target. Hit: 28 (4d8 + 10) bludgeoning damage.

Fathomless Gaze. The Avatar targets one creature it can see within 60 feet of it. The target must make a DC 20 Wisdom saving throw, suffering 55 (10d10) psychic damage on a failed save, or half as much damage on a successful one.

Spellcasting. The Avatar of Umberlee is a 20th-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 22, +14 to hit with spell attacks). The Avatar can cast Control Water and Gust of Wind at will and has the following spells prepared:

- Cantrips (at will): Gust
- 1st level (4 slots): Thunderwave
- 2nd level (3 slots): Misty Step
- 3rd level (3 slots): Call Lightning
- 4th level (3 slots): Control Water
- 5th level (2 slots): Maelstrom
- 6th level (1 slot): Chain Lightning
- 7th level (1 slot): Whirlwind
- 8th level (1 slot): Control Weather
- 9th level (1 slot): Storm of Vengeance

Summon Servants of the Deep. Once per day, the Avatar can summon a Kraken (as per the Monster Manual) that appears in an unoccupied space within 120 feet and acts as an ally of the Avatar. The summon lasts for 1 minute, after which the Kraken returns to the depths.

Sea's Retribution. When a creature hits the Avatar with a melee attack, the Avatar can cause a geyser to erupt under the attacker. The attacker must succeed on a DC 20 Dexterity saving throw or take 22 (4d10) bludgeoning damage and be knocked prone.

The Avatar 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. The Avatar regains spent legendary actions at the start of its turn.

Attack: The Avatar makes one Coral Trident attack or Tail attack.

Move: The Avatar moves up to half its speed without provoking opportunity attacks.

Summon the Depths (Costs 2 Actions): The Avatar summons 2d4 Water Elementals or 1d4 Storm Elementals. The summoned elementals appear in unoccupied spaces within 60 feet of the Avatar and act on their own initiative.

When the Avatar of Umberlee first drops to 0 hit points, instead of dying, it regains 200 hit points and immediately takes a Mythic Action, entering its Mythic Phase. The Avatar is surrounded by a tempestuous aura of churning water and crackling lightning, and its attacks become more ferocious. During its Mythic Phase, the Avatar gains the following Mythic Action, which it can use at the end of another creature's turn:

Tidal Cataclysm (Costs 3 Actions): Umberlee unleashes the full fury of the ocean. Water surges and lightning crashes down in a 60-foot radius centered on the Avatar. Each creature in the area must make a DC 24 Dexterity saving throw, taking 55 (10d10) bludgeoning damage and 55 (10d10) lightning damage on a failed save, or half as much damage on a successful one. The area then becomes difficult terrain due to swirling water and electrical hazards, lasting until the end of the Avatar's next turn.