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

Rejuvenation. A destroyed mummy lord (Xenia Lueltaer) gains a new body in 24 hours if its heart is intact, regaining all its hit points and becoming active again. The new body appears within 5 feet of the Xenia’s heart.

Spellcasting. Xenia is a 20th-level spellcaster. Her spellcasting ability is Wisdom (spell save DC 19, +11 to hit with spell attacks). Xenia has the following cleric spells prepared:

Cantrips (at will): sacred flame, thaumaturgy, Guidance, mending, resistance

1st level (4 slots): command, guiding bolt, shield of faith, bane, cure wounds, guiding bolt

2nd level (3 slots): hold person, silence, spiritual weapon

3rd level (3 slots): animate dead, dispel magic, Bestow curse, clairvoyance, spirit guardians

4th level (3 slots): divination, guardian of faith, banishment, death ward, freedom of movement

5th level (3 slots): contagion, insect plague, mass cure wounds, geas, flame strike

6th level (2 slots): harm, Blade barrier

7th level (2 slots): divine word, plane shift 

8th level (1 slot): Holy aura

9th level (1 slot) gate

Multiattack. Xenia Lueltaer can use her Dreadful Glare and makes one attack with her rotting fist, or she makes two Shadow sword attacks.

Rotting Fist. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (3d6 + 4) bludgeoning damage plus 21 (6d6) necrotic damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or be cursed with mummy rot. The cursed target can't regain hit points, and its hit point maximum decreases by 10 (3d6) for every 24 hours that elapse. If the curse reduces the target's hit point maximum to 0, the target dies, and its body turns to dust. The curse lasts until removed by the remove curse spell or other magic.

Dreadful Glare. Xenia Lueltaer targets one creature she can see within 60 feet of herself. If the target can see her, it must succeed on a DC 16 Wisdom saving throw against this magic or become frightened until the end of the Xenia’s next turn. If the target fails the saving throw by 5 or more, it is also paralyzed for the same duration. A target that succeeds on the saving throw is immune to the Dreadful Glare of all mummies and mummy lords for the next 24 hours.

Shadow Sword. Melee weapon attack: +9 to hit, reach 5 ft., one target. Hit: 8 (1d6+5) piercing damage plus 10 (3d6) necrotic damage and 10 (3d6) poison damage. Xenia can them fill an unoccupied 5-foot cube within five feet of the target with magical darkness, which lasts for one minute.

Xenia Lueltaer 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. Xenia Lueltaer regains spent legendary actions at the start of her turn.

Attack. Xenia Lueltaer makes one attack with her rotting fist or uses her Dreadful Glare.

Blinding spores. Blinding mushroom spores swirls magically around Xenia Lueltaer. Each creature within 5 feet of the her must succeed on a DC 16 Constitution saving throw or be blinded until the end of the creature's next turn.

Blasphemous Word (Costs 2 Actions). Xenia Lueltaer utters a blasphemous word. Each non-undead creature within 10 feet of her that can hear the magical utterance must succeed on a DC 16 Constitution saving throw or be stunned until the end of Xenia’s next turn.

Channel Negative Energy (Costs 2 Actions). Xenia magically unleashes negative energy. Creatures within 60 feet of her, including ones behind barriers and around corners, can't regain hit points until the end of the her next turn.

Whirlwind of Spores (Costs 2 Actions). Xenia magically transforms into a whirlwind of mushroom spores, moves up to 60 feet, and reverts to her normal form. While in whirlwind form, Xenia is immune to all damage, and it can't be grappled, petrified, knocked prone, restrained, or stunned. Equipment worn or carried by Xenia remains in her possession.