Amathé

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

Change Shape. Iymrith magically polymorphs into a female storm giant form , human sorceress form or back into her true form. She reverts to her true dragon form if she dies. Any equipment she is wearing or carrying is absorbed or borne by the new form (the dragon’s choice).

In storm giant form, Iymrith retains her alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Her statistics are otherwise replaced by those of the new form.

In her human form, Iymrith/Amathe is limited to what she was before she became a dragon as shown here. Then No lair actions and no legendary actions.

Spellcasting. Amathé spellcasting ability is Charisma (spell save DC 18, +11 to hit). She can innately cast the following spells, requiring no material components:

Spellcasting. Amathé is an 20th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 18, +11 to hit with spell attacks). Amathé can cast disguise self and invisibility at will and has the following sorcerer spells prepared:

Cantrips (at will): Chill Touch, light, mage hand, Thunderclap, Lightning Lure

1st level (4 slots): Shield, Sleep, mage armor*, Witch Bolt

2nd level (3 slots): Darkness, Mirror Image*, misty step

3rd level (3 slots): counterspell, Hypnotic Pattern, lightning bolt

4th level (3 slots): Dimension Door, Ice Storm, Greater Invisibility

5th level (3 slots): Summon Draconic Spirit, Wall of Stone, Animate Objects

6th level (1 slot): Mass Suggestion

7th level (1 slot): teleport

8th level (1 slot): Earthquake

9th level (1 slot): Mass Polymorph

*Amathé casts these spells on herself before combat.

Dagger. Melee or Ranged Weapon Attack: +10 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 6 (1d4 + 4) piercing damage.