Gorka Tharn

The mummy lord has advantage on saving throws against spells and other magical effects.

A destroyed mummy lord 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 mummy lord's heart.

The mummy can use its Dreadful Glare and makes one attack with its rotting fist.

Melee Weapon Attack +9 to hit, reach 5 ft., one target. 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.

The mummy lord targets one creature it can see within 60 feet of it. If the target can see the mummy lord, it must succeed on a DC 16 Wisdom saving throw against this magic or become Frightened until the end of the mummy'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.

For 1 minute, the mummy lord magically increases in size, along with anything it is wearing or carrying. While enlarged, the mummy lord is Large, doubles its damage dice with its Rotting Fist attack, and makes Strength checks and Strength saving throws with advantage. If the mummy lord lacks the room to become Large, it attains the maximum size possible in the space available.

The mummy lord magically turns Invisible for up to 1 hour or until it attacks, it casts a spell, it uses its Enlarge, or its Concentration is broken (as if Concentrating on a spell). Any equipment the mummy lord wears or carries is Invisible with it.
The stalagmite in the northwest alcove is hollow and serves as Gorka Tharn's sarcophagus. The mummy lord is lodged inside the stalagmite's funnel-shaped interior. When it awakens, the mummy lord uses a Stone Shape spell to create an opening large enough for it to emerge. It destroys any intruders in its lair, then returns to its sarcophagus and its slumber.
At the bottom of the stalagmite's hollow cavity, four 1-foot-tall clay urns contain Gorka Tharn's preserved internal organs, including the mummy lord's shriveled heart. Only by destroying the heart can the characters prevent the mummy lord from rejuvenating. The heart is a Tiny object with AC 5, 25 hit points, and immunity to all damage except fire.

The mummy lord makes one attack with its rotting fist or uses its Dreadful Glare.

Blinding dust and sand swirls magically around the mummy lord. Each creature within 5 feet of the mummy lord must succeed on a DC 16 Constitution saving throw or be Blinded until the end of the creature's next turn.

The mummy lord utters a blasphemous word. Each non-undead creature within 10 feet of the mummy lord that can hear the magical utterance must succeed on a DC 16 Constitution saving throw or be Stunned until the end of the mummy lord's next turn.

The mummy lord magically unleashes negative energy. Creatures within 60 feet of the mummy lord, including ones behind barriers and around corners, can't regain hit points until the end of the mummy lord's next turn.

The mummy lord magically transforms into a whirlwind of sand, moves up to 60 feet, and reverts to its normal form. While in whirlwind form, the mummy lord is immune to all damage, and it can't be Grappled, Petrified, knocked Prone, Restrained, or Stunned. Equipment worn or carried by the mummy lord remain in its possession.