Avatar of Chromium Rhuell

Amphibious. Chromium Rhuell can breathe air and water.

Antimagic Aura. Chromium Rhuell has advantage on saving throws against spells, and any creature making a spell attack against him has disadvantage on the attack roll. If the avatar succeeds on its saving throw against a spell or a spell attack misses it, an additional effect might occur, as determined by rolling a d6:

• 1-2: If the spell affects an area or has multiple targets, it fails and has no effect. If the spell targets only Chromium Rhuell, it has no effect on him and is reflected back at the caster, using the spell slot level, spell save DC, attack bonus, and spellcasting ability of the caster.

• 3-4: No additional effect.

• 5-6: Chromium Rhuell’s aura converts some of the spell’s energy into a burst of destructive force. Each creature within 30 feet of him must make a DC 15 Constitution saving throw, taking 1d6 force damage per level of the spell on a failed save, or half as much damage on a successful one.

Avoidance. Chromium Rhuell will take no damage from succeeding on spell save DC rolls and half damage on failures.

Colossal. Chromium Rhuell is immune to forced movement, does not provoke opportunity attacks, and cannot make opportunity attacks. In addition, whenever the avatar makes a weapon attack, regardless of whether the attack hits or misses, each creature within 20 feet of the attack’s target other than the target or the avatar himself must succeed on a DC 27 Dexterity saving throw or takes half the attack's damage.

Discorporation. When Chromium Rhuell dies, his body is destroyed, but his essence travels back to his domain in the Unseen, and he cannot take physical form for a time.

Freedom of Movement. Chromium Rhuell ignores difficult terrain, and magical effects can’t reduce its speed or cause it to be restrained. It can spend 10 feet of movement to escape from nonmagical restraints or being grappled.

Legendary Resistance (5/Day). If Chromium Rhuell fails a saving throw, he can choose to succeed instead.

Limited Magic Immunity. Chromium Rhuell can't be affected or detected by spells of 6th level or lower unless he wishes to be. he has advantage on saving throws against all other spells and magical effects.

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

Magic Weapons. Chromium Rhuell's weapon attacks count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks.

Mimicry. Chromium Rhuell can mimic sounds he has heard, including voices. Creatures that hear the sounds can tell they are imitations with a successful Wisdom (Insight) check opposed by your Charisma (Deception) check.

Otherworldly Perception. Chromium Rhuell can sense the presence of any creature within 300 feet of him that is invisible or on the Ethereal Plane. He can pinpoint such a creature that is moving.

Prismatic Resurgence (Recharges after a Short or Long Rest). If Chromium Rhuell would be reduced to 0 hit points, his current hit point total instead is set to 300 hit points, he recharges his Breath Attacks, and he regains any expended uses of Legendary Resistance. Additionally, the avatar can now use the options in the "Mythic Actions" section for 1 hour.

Reactive. Chromium Rhuell can take one reaction on every turn in combat.

Regeneration. Chromium Rhuell regains 30 hit points at the start of its turn. If the monster takes acid or fire damage, this trait doesn't function at the start of the monster’s next turn. The monster dies only if it starts its turn with 0 hit points and doesn't regenerate.

Shapechanger. Chromium Rhuell can use his action to polymorph into any creature, humanoid or otherwise, he has seen, or back into his true form. Besides his size and AC, the avatar's other statistics are the same in each form. Any equipment he is wearing or carrying isn’t transformed. Chromium Rhuell reverts to his true form if he dies.

Siege Monster. Chromium Rhuell deals double damage to objects and structures.

Telepathic Shroud. Chromium Rhuell is immune to any effect that would sense his emotions or read his thoughts, as well as all divination spells.

Multi-Attack. Chromium Rhuell can use his Frightful Presence. The avatar makes one Bite attack, one Claw attack, and one Tail attack.

Bite. Melee Weapon Attack: +19 to hit, reach 25 ft., one target. Hit: 23 (2d12 + 10) piercing damage plus 19 (3d12) force damage.

Claw. Melee Weapon Attack: +19 to hit, reach 20 ft., one target. Hit: 21 (2d10 + 10) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 20) and is restrained until this grapple ends. The aspect can have only one creature grappled this way at a time.

Tail. Melee Weapon Attack: +19 to hit, reach 25 ft., one target. Hit: 23 (2d12 + 10) bludgeoning damage. If the target is a creature, it must succeed on a DC 27 Strength saving throw or be knocked prone.

Frightful Presence. Each creature of Chromium Rhuell's choice that is within 240 feet of the avatar and aware of him must succeed on a DC 26 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the avatar’s Frightful Presence for the next 24 hours.

Spellcasting. Chromium Rhuell's spellcasting ability is Charisma (spell save DC 26, +10 to hit with spell attacks). He can innately cast the following spells, requiring no material components.

At will: detect magic

3/day each: dispel magic, chromatic orb (9th Level)

1/day each: power word stun, prismatic spray, divine word

Petrifying Cloud Breath Attack (Recharge 5-6): Chromium Rhuell Breathes petrifying gas in a 30-foot cone. Each creature in that area must succeed on a DC 17 Constitution saving throw. On a failed save, a target begins to turn to stone and is Restrained. The Restrained target must repeat the saving throw at the end of its next turn. On a success, the Effect ends on the target. On a failure, the target is Petrified until freed by the Greater Restoration spell or other magic.

Acid Spray Breath Attack (Recharge 5-6): Chromium Rhuell spits acid in a 120-foot line that is 10 feet wide. Each creature in that line must make a DC 27 Dexterity saving throw, taking 67(15d8) acid damage on a failed save, or half as much damage on a successful one.

Lightning Bolt Breath Attack (Recharge 5-6):  Chromium Rhuell discharges lightning in a 120-foot line that is 10 feet wide. Each creature in that line must make a DC 27 Dexterity saving throw, taking 88 (16d10) lightning damage on a failed save, or half as much damage on a successful one.

Poison Haze Breath Attack (Recharge 5-6): Chromium Rhuell breathes poisonous gas in a 90-foot cone. Each creature in that area must make a DC 27 Constitution saving throw, taking 77 (22d6) poison damage on a failed save, or half as much damage on a successful one.

Razing Inferno Breath Attack (Recharge 5-6): Chromium Rhuell breathes fire in a 90-foot cone. Each creature in that area must make a DC 27 Dexterity saving throw, taking 91 (26d6) fire damage on a failed save, or half as much damage on a successful one.

Freezing Lance Breath Attack (Recharge 5-6): Chromium Rhuell Breathes an icy blast in a 90-foot cone. Each creature in that area must make a DC 27 Dexterity saving throw, taking 72 (16d8) cold damage on a failed save, or half as much damage on a successful one.

Enter the description for how bonus actions work for your monster here.

Spellcasting. 

5/day each: absorb elements

3/day each: counterspell

Attack. Chromium Rhuell makes one Claw, Bite or Tail attack.

Cast a spell (Costs 2 Actions). Chromium Rhuell uses Spellcasting.

Furious Bite (Costs 2 Actions). Chromium Rhuell makes one Bite attack. If the attack hits a creature, the target must succeed on a DC 27 Wisdom saving throw or become frightened of the aspect until the end of its next turn.

Breath Weapon. (Costs 2 Actions). Chromium Rhuell can use one of his breath weapons if it recharged.

If Chromium Rhuell's Prismatic Resurgence trait was activated in the last hour, he can use the options below as legendary actions.

Gaze into the Iris (Costs 2 Actions). Chromium Rhuell targets a creature he is grappling. The creature must succeed on a DC 25 Charisma saving throw or take 44 (8d10) psychic damage and be banished to the Unseen. At the start of the avatar’s next turn, the creature reappears in an unoccupied space within 10 feet of the avatar.

Prismatic Flare (Costs 3 Actions). Chromium Rhuell flares with ethereal energy. Each creature of the avatar’s choice in a 60-foot-radius sphere centered on him must make a DC 27 Dexterity saving throw. On a failed save, the creature takes 39 (6d12) damage of a type chosen by the aspect: acid, bludgeoning, cold, fire, force, lightning, necrotic, piercing, poison, psychic, radiant, slashing, or thunder. On a successful save, the creature takes half as much damage.