Natsuko's innate spellcasting is Wisdom (spell save DC23, +15 to hit with spell attacks). Natsuko can cast the following spells, requiring only verbal components.
Legendary Resistance (3/day): If Natsuko fails a saving throw, she can choose to succeed instead.
Magic Resistance: Natsuko has advantage on saving throws against spells and other magical effects.
Magic Weapon: Natsuko's attacks are magical.
Unbridled Movement: Natsuko's movement is unaffected by difficult terrain, and spells and other magical effects cannot reduce her speed. In addition, she can move through hostile creature's space, regardless of the creature's size.
Multiattack: Natsuko uses her Manifest Duplicity. She can then make three attacks: one bite and two claw.
Bite:Melee Weapon Attack +16 to hit, reach 10 ft. one target. Hit:22 (4d6+8) piercing damage.
Claw:Melee Weapon Attack +16 to hit, reach 10 ft. one target. Hit:15 (2d6+8) slashing damage.
Manifest Duplicity: Natsuko creates a perfect illusion of herself that lasts for 1-minute. The duplicate appears in an unoccupied space of her choice within 60 feet. The duplicate is indistinguishable from the real Natsuko, is considered a monster and shares Natsuko's statistics. It does not have its own turns, but it can take a reaction each round. Natsuko may only have 3 total duplicates active at a time. At the start of her turn each round, Natsuko can transfer her consciousness to one of her duplicates, swapping places with it. She may also use her full movement speed divided between all of her duplicates on her turn.
Natsuko 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. Natsuko regains all legendary action points at the start of her turn.
Move: Natsuko may divide up half her movement speed to move herself and her duplicates.
Bite: Natsuko or a duplicate of her choice makes a bite attack.
The Trickster (Costs 2): Natsuko chooses one of her duplicates to immediately take a full turn in combat. The duplicate can't cast spells and can't Manifest Duplicity.