Archangel Sera

Butterfly Garden (Mythic Trait; Recharges after a Short or Long Rest). If Sera is reduced to 0 hit points, she doesn’t die or fall unconscious. Instead, she regains 50 hit points and gains 50 temporary hit points. In addition, the area around Sera is occupied by hundreds of butterflies. For as long as Sera has temporary hit points from this feature the DC for Unruly Illusions is set to 11.

Legendary Resistance (3/Day). If Sera fails a saving throw, she can choose to succeed instead.

Unruly Illusions. Each time a creature attacks Sera, she rolls a d20. If she rolls a 16 or higher, the attacker targets a butterfly disguised as Sera instead. A Detect Magic spell can determine if any butterflies are disguising themselves, allowing the caster to ignore this feature. The caster can also use a reaction to another creature taking their action to allow them to ignore the feature. Those able to discern the illusions can also use a reaction to another creature taking their action to allow them to ignore the feature.

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

Luring Light. At the start of each of Sera's turns 1d2 Swarms of Fallen Butterflies are conjured to aid her. They take their turn in initiative after her, and she can give them verbal commands them as a free action on her turn. She can have a maximum of six swarms conjured at once.

Multiattack. Sera makes two attacks with Fallen Whip or Psychic Lash, or a mix of the two.

Fallen Whip. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 22 (4d6 + 8) slashing damage plus 18 (4d8) necrotic damage. Creatures that are hit by this whip must succeed on a DC 22 Wisdom saving throw or be plunged into an illusory reality.

If the creature is of good alignment then they believe they are banished to a celestial holding room where they are unable to use magic or escape. Their real body is Stunned until they escape. The creature can make a DC 12 Wisdom saving throw at the end of each of their turns to try and escape. If the creature is neutral then their most recent actions decide if they are either good or evil using Sera's standards.

If the creature is of evil alignment then they believe they are banished to the prison of Sera's true form. Whenever a creature starts their turn in this realm they must succeed on a DC 24 Wisdom saving throw or take 49 (14d6) psychic damage. The creature can make a DC 12 Wisdom saving throw at the end of each of their turns to try and escape. Their real body is Stunned until they escape.

Psychic Lash. Ranged Spell Attack: +17 to hit, range 120 ft., one target. Hit: 24 (7d6) psychic damage, and the target must make a DC 24 Intelligence saving throw. On a failed save, the creature suffers the effect of the confusion spell. The effect lasts until the start of Sera’s next turn. Sera doesn’t need to concentrate on the spell.

Teleport. Sera magically teleports, along with any equipment she is wearing or carrying, up to 120 feet to an unoccupied space he can see.

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

Fallen Holy Magic (Costs 2 Actions). Sera uses Teleport or casts Mental Prison. The DC for this spell is 24

Attack. Sera makes one Psychic Lash attack.

If Sera’s mythic trait is active, she can use the options below as legendary actions, as long as she has temporary hit points from her Butterfly Garden.

Swarm (Costs 2 Actions). A group of fallen butterflies fill a 15-foot-radius sphere centered on a point Sera chooses within 120 feet. The sphere spreads around corners. The sphere remains for 1 minute, and its area is lightly obscured. The sphere’s area is difficult terrain. When the area appears, each creature in it must make a DC 24 Intelligence saving throw. A creature takes 22 (4d10) psychic damage on a failed save, or half as much damage on a successful one. A creature must also make this saving throw when it enters the attack’s area for the first time on a turn or ends its turn there.