Circe

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

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

Master of Transmutation. Whenever Circe casts a transmutation spell that targets exactly one creature other than herself, that spell instead targets 1d4 creatures.

Uncultured Swine. Male humanoid creatures have disadvantage on saving throws against transmutation spells cast by Circe.

Spellcasting. The archmage is an 20th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 20, +12 to hit with spell attacks).

Cantrips (at will): dancing lights, fire bolt, mage hand, prestidigitation, shocking grasp, vicious mockery

1st level (4 slots): detect magic, expeditious retreat, identify, Tasha's hideous laughter, unseen servant

2nd level (3 slots): detect thoughts, enlarge/reduce, skywrite

3rd level (3 slots): counterspell, fireball, sending

4th level (3 slots): compulsion, conjure woodland beings, dimension door, polymorph

5th level (3 slots): animate objects, modify memory, scrying, telekinesis

6th level (2 slots): disintegrate, true seeing

7th level (2 slots): forcecage, teleport

8th level (1 slot): animal shapes, glibness

9th level (1 slot): true polymorph

Dagger. Melee or Ranged Weapon Attack: +6 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

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

Blast. Circe casts a cantrip.

Shrink (Costs 2 Actions). Circe casts enlarge/reduce, choosing the reduce effect, using a spell slot as normal.

Filthy Swine (Costs 3 Actions). Circe casts polymorph, transforming the target into a [monster]boar[/spell], using a spell slot as normal.