Urza, the Mad Sovereign

Amphibious. Urza can breathe air and water.

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

Magic Weapons. Urza's weapon attacks are magical.

Legendary Eminence (4/Day). If Urza fails a saving throw, she can choose to succeed instead. However, each time Urza uses her Legendary Eminence, the maximum number of spectral tendrils (see Spectral Tendrils) that she can summon decreases by two until she regains her uses of this trait.

Maddening Presence of the Sovereign. Any creature hostile to Urza that starts its turn within 200 feet of her must make a DC 26 Wisdom saving throw unless Urza is unconscious. On a failed save, a creature is infected with Yellow Psychosis and is frightened until the start of its next turn. While frightened in this way, a creature's speed is halved, and it takes a -5 penalty to all attack rolls, saving throws, and ability checks. This effect ignores immunity to being frightened, and a creature that is normally immune to being frightened instead has advantage on its saving throw against this effect. Additionally, a creature that normally has advantage on saving throws against being frightened does not have advantage on its saving throw against this effect. If a creature's saving throw is successful, the creature is immune to Urza's Maddening Presence of the Sovereign for the next 24 hours.

Spectral Tendrils. Urza can have up to eight spectral tendrils summoned at a time. Each tendril can be attacked (AC 19; 40 hit points; immunity to poison and psychic damage). Destroying a tendril deals no damage to Urza, who can resummon any number of replacement tendrils on her next turn.

3rd-Degree Yellow Psychosis. Urza has disadvantage on Intelligence, Wisdom, and Charisma ability checks and saving throws. Additionally, she has the following long-term madness flaw: "Anyone who is not under my protection is a threat to those who are."

Multiattack. Urza makes three attacks. She can replace one attack with her Swallow.

Dark Bolt. Ranged Spell Attack: +18 to hit, range 150 ft., one target. Hit: 25 (5d6 + 10) cold damage. If the target is a creature, it can't regain hit points until the start of Urza's next turn.

Spectral Tendril. Melee Spell Attack: +18 to hit, reach 80 ft., one target. Hit: 20 (2d10 + 10) force damage. If the target is a creature, it is grappled (escape DC 26). Until the grapple ends, the target is restrained and takes 12 (2d10) force damage at the start of each of its turns, and Urza can't use the same tendril on another target.

Trident. Melee or Ranged Weapon Attack: +17 to hit, reach 15 ft. or range 40/120 ft., one target. Hit: 21 (4d6 + 9) piercing damage, or 25 (4d8 + 9) piercing damage if used with two hands to make a melee attack, plus 15 (5d6) lightning damage. If Urza makes a ranged attack with her trident, the trident magically returns to her hand after the attack.

Swallow. Urza targets a Huge or smaller creature that she can see within 10 feet of her. The target must succeed on a DC 22 Dexterity saving throw. On a failure, the target is swallowed. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside of Urza, and it takes 50 (16d6) acid damage at the start of each of Urza's turns.

If Urza takes 40 damage or more on a single turn from a creature inside her, she must succeed on a DC 25 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Urza. If Urza dies, a swallowed creature is no longer restrained by her and can escape from her corpse by using 15 feet of movement, exiting prone.

Weavesong (Recharge 4-6). Urza sings a song of arcane power that can be heard within 300 feet of her, casting one of the following magical effects on up to four creatures of her choice that can hear her song:

• Song of Enervation. Each target must make a DC 26 Constitution saving throw. On a failed save, a target takes 50 (12d8) necrotic damage and the target's hit point maximum is reduced by an amount equal to the necrotic damage taken. The target dies if this effect reduces its hit point maximum to 0. This reduction lasts until removed by the greater restoration spell or similar magic. On a successful save, a target takes half as much damage, and its hit point maximum isn't reduced.
• Song of Glamour. Each target must succeed on a DC 26 Wisdom saving throw or move up to its speed to a space of Urza's choice and make one weapon attack against another creature of Urza's choice if it is able. A target that is immune to being charmed is immune to this effect.
• Song of Restoration. Each target, if it is willing, regains 50 (12d8) hit points and is freed from any disease, poison, blindness, deafness, or any levels of exhaustion.
• Song of Cancellation. If a target is under the effects of a spell of 4th level or lower, the spell ends on the creature. In addition, if a target is concentrating on a spell, it must succeed on a DC 26 concentration check or lose concentration on the spell.

Spellcasting. Urza casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 26):

At will: detect magic, detect thoughts, druidcraft, greater restoration, sending, thaumaturgy

3/day each: flesh to stone, heal, regenerate (as an action), synaptic static

1/day each: dominate monster, plane shift, resurrection (as an action), teleport

Sovereign's Maddening Gaze. Urza targets a creature that she can see within 120 feet of her. If the target can see Urza, it must succeed on a DC 26 Intelligence saving throw or take 40 (12d6) psychic damage and become infected with Yellow Psychosis.

Change Size. Urza magically changes her size to Large, or back to her true size.

Summon Living Nightmares (Recharge 5-6). Urza summons 5 physical manifestations of her Yellow Psychosis insanity. These manifestations use the statistics of shadow horrors, have 5 hit points each, and appear in unoccupied spaces that Urza chooses within 120 feet of her. They act as Urza's allies and take their turns immediately after hers. They remain until they die, Urza dismisses them as a bonus action, or Urza is cured of her Yellow Psychosis.

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

Attack. Urza makes an attack.

Sovereign's Maddening Gaze. Urza uses Sovereign's Maddening Gaze.

Cat and Mouse (Costs 2 Actions). Urza moves up to her speed without provoking opportunity attacks and can use Swallow.

Medley of Spell and Song (Costs 3 Actions). Urza uses Spellcasting or Weavesong, if available.