Innate Spellcasting. Graz'zt's spellcasting ability is Charisma (spell save DC 23). Demogorgon can innately cast the following spells, requiring no material components:
Legendary Resistance (3/Day). If Graz'zt fails a saving throw, he can choose to succeed instead. Magic Resistance. Graz'zt has advantage on saving throws against spells and other magical effects. Magic Weapons. Graz'zt's weapon attacks are magical.
Multiattack. Graz'zt attacks twice with Wave of Sorrow. Wave of Sorrow (Greatsword). Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (4d6 + 6) slashing damage plus 10 (3d6) acid damage. Teleport. Graz'zt magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.
Shapechanger. Graz'zt can use his bonus action to polymorph into a form that resembles a Medium humanoid, or back into his true form. Aside from his size, his statistics are the same in each form. Any equipment he is wearing or carrying isn't transformed.
Graz'zt 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. Graz'zt regains spent legendary actions at the start of his turn. Attacks. Graz'zt attacks once with Wave of Sorrow. Dance, My Puppet! One creature charmed by Graz'zt that Graz'zt can see must use it's reaction to move up to it's speed as Graz'zt directs. Sow Discord. Graz'zt casts crown of madness or dissonant whispers. Teleport. Graz'zt uses his teleport action.
On Initiative count 20 (losing initiative ties), Graz'zt can take a lair action to cause one of the following effects: he can't use the same effect two rounds in a row:
Graz'zt's mere presence in a plane other than his own bends it to his shape. His lair is the fane of this change, often it is where he was summoned or where he stays for extended time, his energies pooling around him.
The region containing Graz'zt's lair is warped by his magic, creating one or more of the following effects: