Special Equipment.

Asteria wears Winged Boots, which grant her a flying speed (included in her statistics). She also carries one half of a pair of Sending Stones; the other half of the pair is held by Euryale.

Guardian Aura.

Whenever a creature of Asteria's choice within 30 feet of her makes a saving throw, Asteria can give the creature advantage on the saving throw (no action required). This trait doesn't function if Asteria has the incapacitated condition.

Legendary Resistance (3/Day).

If Asteria fails a saving throw, she can choose to succeed instead.

Actions

Multiattack.

Asteria makes two Radiant Blade attacks and uses Bursting Benediction.

Radiant Blade.

Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) slashing damage plus 13 (3d8) radiant damage.

Bursting Benediction.

Asteria causes a burst of magical energy to envelop one creature she can see within 60 feet of herself. The target must make a DC 19 Dexterity saving throw, taking 40 (9d8) force damage on a failed save, or half as much damage on a successful one. Asteria or another creature that she can see within 60 feet of herself then regains 10 hit points.

Spellcasting.

Asteria casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 19):

At will: Guidance, Light, Thaumaturgy
2/day each: Bless, Freedom of Movement, Greater Restoration, Plane Shift (self only), Protection from Evil and Good, Revivify

Bonus Actions

Empowering Aegis (Recharge 4–6).

Asteria summons a spectral version of her shield, which orbits and bolsters one creature of Asteria's choice that she can see within 60 feet of herself. The spectral shield lasts until the start of Asteria's next turn. While the shield is orbiting the creature, the creature has half cover, is immune to the frightened condition, and makes weapon attack rolls with advantage.

Legendary Actions

Asteria can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Asteria regains spent legendary actions at the start of its turn.

Brazen Strike. Asteria makes one Radiant Blade attack.
Nimble Sprint. Asteria moves up to her speed. This movement doesn't provoke opportunity attacks.
Cast a Spell (Costs 2 Actions). Asteria uses Spellcasting.