Aetherion

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

Elemental Mastery: Aetherion can control and manipulate the elements of Earth, Water, Fire, Air, and Aether. It can cast the following spells at will, without expending spell slots:

• Control Water
• Wall of Fire
• Earthquake
• Storm of Vengeance
• Flame Strike
• Air Walk
• Banishment (only on planar creatures, once per day)

Aether’s Grasp: Aetherion can use its Aether-based powers to manipulate space and time in a limited area. Once per long rest, Aetherion can cast Time Stop or Plane Shift (self only).

Elemental Shift (Recharge 5-6): As a bonus action, Aetherion can shift its form to embody one of the four classic elements. The shift lasts for 1 minute and grants Aetherion new abilities based on the chosen element:

• Fire Form: Aetherion becomes wreathed in flames. Any creature that ends its turn within 5 feet of Aetherion takes 15 (4d6) fire damage. It can also cast Fireball (save DC 18) as a bonus action once per turn.

• Water Form: Aetherion becomes a living tidal wave. It gains resistance to fire damage and can cast Tidal Wave (save DC 18) as a bonus action once per turn.

• Earth Form: Aetherion's body becomes stone and crystal, increasing its AC by +2. It gains resistance to lightning damage and can use a Rock Throw (range 120 ft., one target, 30 (6d6) bludgeoning damage) as a bonus action once per turn.

• Air Form: Aetherion becomes a swirling vortex of wind. It gains resistance to acid damage and can cast Fly on itself as a bonus action, also creating a gust of wind in a 30-foot cone, forcing creatures to make a DC 18 Strength saving throw or be pushed 15 feet away and knocked prone.

Multiattack: Aetherion makes three attacks, one with each of its elemental arms (Fire, Water, and Earth).

• Fire Slam (Melee Weapon Attack): +16 to hit, reach 15 ft., one target. Hit: 40 (6d10+9) fire damage.
• Water Strike (Melee Weapon Attack): +16 to hit, reach 15 ft., one target. Hit: 40 (6d10+9) bludgeoning damage plus 20 (4d6) cold damage.
• Earthquake Slam (Melee Weapon Attack): +16 to hit, reach 15 ft., one target. Hit: 45 (7d10+9) bludgeoning damage, and the target must succeed on a DC 18 Dexterity saving throw or be knocked prone.

Elemental Fury (Recharge 5-6): Aetherion unleashes the combined power of the elements, causing chaos in a 60-foot radius centered on itself. All creatures in that area must make a DC 20 Dexterity saving throw. On a failed save, creatures take 70 (10d10) damage of a random elemental type (Fire, Cold, Lightning, Thunder, or Force) and are knocked prone. On a successful save, creatures take half as much damage and are not knocked prone.

• Lair Actions

  On initiative count 20 (losing initiative ties), Aetherion can take a lair action to cause one of the following effects:

  1. Elemental Surge: Aetherion can cause a burst of elemental energy to flood an area. All creatures within 30 feet of a point Aetherion can see must make a DC 18 Constitution saving throw or be poisoned for 1 minute, taking 10 (3d6) poison damage at the start of each of their turns.

  2. Aetheric Pulse: Aetherion sends a pulse of Aether magic through the ground. Creatures within 60 feet of Aetherion must make a DC 18 Wisdom saving throw or be stunned until the start of Aetherion's next turn.

  3. Summon Elemental Forces: Aetherion summons a powerful elemental manifestation to fight for it. This creature is one CR 15 elemental of the appropriate type (Fire, Water, Earth, or Air).

Aetheric Shield: When Aetherion is hit by a melee or ranged attack, it can use its reaction to reduce the damage by half by creating a shield of energy from the Aether. This shield lasts until the start of Aetherion's next turn.

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

Command Ally. The warlord targets one ally it can see within 30 feet of it. If the target can see or hear the warlord, the target can make one weapon attack as a reaction and gains advantage on the attack roll.

Weapon Attack. The warlord makes one Greatsword or Shortbow attack.

Frighten Foe (Costs 2 Actions). The warlord targets one creature it can see within 30 feet of it. If the target can see or hear it, the target must succeed on a DC 16 Wisdom saving throw or be frightened of the warlord until the end of warlord’s next turn.