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

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

Magic Weapons. Ylleshka's weapon attacks are magical.

Reactive. Ylleshka can take two reactions on every turn in a combat.

Two Heads. Ylleshka has advantage on saving throws against being blinded, deafened, stunned, and knocked unconscious.

Multiattack. Ylleshka makes seven attacks: six with her longswords and one with her tail.

Longsword. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 22 (4d8 + 4) slashing damage.

Tail. Melee Weapon Attack: +10 to hit, reach 10 ft., one creature. Hit: 15 (2d10 + 4) bludgeoning damage. If the target is Medium or smaller, it is grappled (escape DC 20). Until this grapple ends, the target is restrained, Ylleshka can automatically hit the target with its tail, and the marilith can't make tail attacks against other targets.

Sweeping Blades (Recharge 6). Ylleshka makes a sweep with her longswords, and each creature within 10 feet of her must make a DC 18 Dexterity saving throw. A creature takes 112 (24d8 + 4) slashing damage on a failed save, or half as much damage on a successful one.

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

Parry. Ylleshka adds 6 to her AC against one melee attack that would hit her. To do so, Ylleshka must see the attacker and be wielding a melee weapon.

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

Attack. Ylleshka makes a longsword attack.

Teleport. Ylleshka uses her Teleport action.