Azelf

Legendary Resistance (3/Day): If the Azelf fails a saving throw, it can choose to succeed instead.

Amphibious: The Azelf can breathe air and water.

Being of Willpower: Once per day, as an action, the Azelf can choose a creature within 60 feet and either bestow it willpower or destroy its current willpower. An unwilling target can make a DC 19 Wisdom saving throw, becoming immune to this effect for 48 hours on a successful save.

• Bestow Willpower: The target is given the courage and determination in mind and body to carry forward. The target has advantage on all ability checks, attack rolls and saving throws for 1 month. If a creature that has previously been bestowed willpower is targeted by the Azelf's Destroy Willpower during the duration, these effects end early and their willpower returns to normal.
• Destroy Willpower: The target is overwhelmed by thoughts of giving up. The target has disadvantage on all ability checks, attack rolls and saving throws for 1 week. At the end of every 24 hours, the creature can repeat its saving throw against this effect. On a success, the effect ends and their willpower is restored. The effect can also be ended by greater restoration, heal, or wish. If a creature whose willpower has previously been destroyed is targeted by the Azelf's Bestow Willpower during the duration, these effects end early and their willpower returns to normal.

Flyby: The Azelf doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Guardian of the Lake: The Azelf knows the exact location of Mesprit and Uxie while any are on the same plane of existence, and can sense what they sense. The Azelf ignores the range restriction on its telepathy when communicating with them, though it can't extend into other planes of existence.

Immutable Form: The Azelf is immune to any spell or effect that would alter its form.

Innate Spellcasting (Psionics): The Azelf's innate spellcasting ability is Wisdom (spell save DC 23, +15 to hit with spell attacks). It can innately cast the following spells, requiring no components:
At will: bestow curse, blindness/deafness, compulsion, command, dispel magic, hold person, magic circle, ray of enfeeblement
3/day each: commune with nature, geas, dominate person, private sanctum
1/day each: antimagic field, dominate monster, imprisonment

Levitate: The Azelf ignores ground-based difficult terrain and spells.

Magic Resistance: The Azelf has advantage on saving throws against spells and other magical effects.

Petrifying Body: A creature that touches the Azelf or hits it with a melee attack while 5 feet of it must make a DC 19 Constitution saving throw. If the saving throw fails by 5 or more, the creature is instantly petrified. Otherwise, a creature that fails the saving throw begins to turn to stone and is restrained. The restrained creature must repeat the saving throw at the end of its next turn, becoming petrified on a failure or ending the effect on a success. The petrification lasts until the creature is freed by the greater restoration spell or other magic.

Shielded Mind: The Azelf is immune to scrying and to any effect that would sense its emotions, read its thoughts, or detect its location, unless it allows it.

Confusion: Ranged Spell Attack: +15 to hit, range 60 ft., one creature. Hit: 26 (4d8 + 9) psychic damage and the target must succeed at a DC 18 Wisdom saving throw. On a failed save, the target is confused (as per the confusion spell) until the end of its next turn.

Detect: The next time the Azelf would take damage from an attack or be affected by a condition before the end of the round, it takes no damage or is unaffected by the condition. For every consecutive use of this action, roll a d20, the DC being 5 + an additional 5 for every consecutive use after the first. On a failure, this action fails.

Extrasensory: Ranged Spell Attack: +15 to hit, range 60 ft., one creature. Hit: 36 (5d10 + 9) psychic damage and the target must succeed at a DC 17 Constitution saving throw. On a failed save, the target is stunned until the end of their next turn.

Last Resort: Ranged Spell Attack: +15 to hit, range 60 ft., one target. Hit: 41 (5d12 + 9) force damage. The Azelf can only take this action if it has taken every other action at least once this combat.

Mystical Power (Recharge 5-6): Ranged Spell Attack: +15 to hit, range 60 ft., one target. Hit: 36 (5d10 + 9) psychic damage. If the attack hits and the Azelf's Strength score is higher than its AC, each of its attacks deal an additional die of damage for 1 minute. Otherwise, it gains +1 to its AC for 1 minute.

Uproar: The Azelf chooses a creature within 60 feet that can hear it and makes a ranged spell attack against that creature. On a hit, the target takes 21 (3d8 + 8) thunder damage and the Azelf creates an uproar in a 60-foot cube, centred on itself, which moves with it. Creatures within that area cannot be put to sleep by magical means, and any sleeping creatures wake up when they enter the area of uproar. Creatures in an area where sound is prevented, such as the area of a silence spell, are unaffected. The Azelf must use either its action or bonus action on each of its subsequent turns to continue the uproar, up to a maximum duration of 5 rounds, or the uproar ends at the start of its next turn.

The Azelf can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The Azelf regains spent legendary actions at the start of its turn.

Nasty Plot: The Azelf gains advantage on its next attack roll. If the attack hits, it deals an additional die of damage.

Explosion (Costs 2 Actions): All creatures within 60 feet of the Azelf must make a DC 19 Dexterity saving throw, taking 27 (4d8 + 9) fire damage and falling prone on a failed save, or half as much damage and not falling prone on a successful one. The Azelf's hit points are then reduced by an amount equal to a quarter of its hit point maximum.

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