Avatar of Set

Seething Cold. Whenever the avatar is subjected to cold damage, the avatar's regeneration increases to 50 until the end of it's next turn.

Seething Cold. Any creature that is within 5ft of the avatar and hits  the avatar with a melee attack must make a DC 19 Dexterity saving throw or take 2d6 poison damage.

Innate Spellcasting. The avatar's innate spellcasting ability is Charisma (Spell save DC 22). The avatar can innately cast the following spells, requiring no material components:

At Will: Animal Friendship (Snakes Only), Blight, Fear, Suggestion.

Legendary Resistance 5/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.

Regeneration.  The avatar regains 30 hit points at the start of its next turn. If the avatar takes at least 15 points of fire damage, this trait doesn't function at the start of it's next turn. The avatar dies if it is reduced to 0 hit points and can't regenerate.

Godly Essence.  If the avatar is reduced to 0 hit points or less the avatar disappears from the material plane back to his prison plane with the other betrayer gods, unable to take physical form for 1d10 years.

Multiattack. The avatar uses it's Hypnotic Undulations ability and then makes up to three attacks with it's tail, it's claws, it's bite, or with it's Phlogitoxin spit.

Tail. Melee Weapon Attack: +15 to hit, reach 20ft, one target. Hit 16 (3d8+8) Bludgeoning damage.

Bite. Melee Weapon Attack: +15 to hit, reach 15ft, one target. Hit 14 (2d10+8) piercing + 6 (2d6) poison damage.

Claw. Melee Weapon Attack: +15 to hit, reach 15ft, one target. Hit 10 (2d6+8) piercing + 6 (2d6) poison damage. The avatar can choose to negate damage to grapple the target (escape DC 22). Until this grapple ends the creature is restrained, and the avatar can't use its claw attack on another target.

Swallow Whole. The avatar makes one bite attack against a Large or smaller creature that it is grappling. If the attack hits, the creature is swallowed whole and the grapple ends. The swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the avatar. At the start of the avatars turn any creatures swallowed whole take 18 (6d6) poison damage, as poisonous gas and liquid fill the avatars stomach. The avatar can have up to 8 medium creatures or 2 large creatures swallowed at any time. If the avatar takes 30 damage or more on a single turn from the swallowed creature, the avatar must succeed on a Constitution saving throw, DC being the damage halved, minimum of 15. If the avatar dies, any swallowed creatures  are regurgitated out before the avatar disappears back to his prison plane.

Phlogitoxin Spit. Ranged Weapon Attack: +13 to hit, range 60ft, one target. Hit 15 (4d6+6) poison damage.

Phlogitoxin Breath (Recharge 5-6). The avatar exhales poisonous gas in a 50ft cone. Each creature in the area must make a DC 22 Dexterity saving throw, taking 12d6 poison damage and gain the poisoned condition on a failed save, or half as much damage on a successful save with no poisoned condition.

Hypnotic Undulations. The avatar's scales seem to glow with dark-green light emitted from its core as it stares down at three targets within 30ft. The avatar chooses 3 creatures within 30ft and if the target can see the avatar they must succeed on a DC 20 Wisdom saving throw against this magic or be charmed until the end of the avatars next turn. The charmed target is stunned. If the target's saving throw is successful, the target is immune to the avatar's gaze for the next 24 hours.

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

The avatar can take 5 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 creatures turn. The avatar regains any spent legendary action points at the start of it's turn.

Poisonous explosion (Costs 3 Actions). The avatar lets out a massive poisonous cloud from it's core. Each creature within 20 feet of the avatar must succeed on a DC 22 Dexterity saving throw or take (3d6) poison damage

Phlogitoxin Spit (Cost 2 actions). The avatar makes one Phlogitoxin spit attack.

Tail Swipe. The avatar makes one tail attack.

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

Mythic Action Name (Costs # Actions). Enter the description for your mythic action.