Buer

Immortality. As an archdevil, Buer cannot be killed on any plane outside of the Nine Hells by anything other than the First Blade, but instead merely disippates back to Tartarus. If Buer is reduced to 0 hit points anywhere other than the Nine Hells, her soul refuses to accept its fate and lives on as a disembodied spirit that fashions a new body for itself after 1d10 x 100 years. Buer regains consciousness after this time has passed, and regains all hit points.

Legendary Resistance (3/Day). If Buer fails a saving throw, she can choose to succeed instead.

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

Regeneration. Buer regains 10 hit points at the start of her turn. If she takes Cold or Radiant damage, this trait doesn't function at the start of his next turn. Buer dissipates only if she starts his turn with 0 hit points and doesn't regenerate.

Multiattack. Buer makes two attacks with Aegeria.

Aegeria. Melee Attack Roll: +10, reach 10 ft. Hit: 7 (1d6 + 4) Bludgeoning damage plus 11 (2d10) Necrotic damage, and the target is cursed for 1 minute. A cursed creature has the following effect at the start of each of its turns. Wisdom Saving Throw: DC 22. Failure: The target takes the Dodge action. Success: The target acts normally.

Pneumousia. Ranged Attack Roll: +11, range 150/600 ft. Hit: 8 (1d8 + 5) Piercing damage plus 14 (4d6) Fire damage.

Spellcasting. Buer casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 22):

At Will: Find Familiar (Imp only)

2/Day Each: Flame Strike

1/Day Each: Harm, Heal, Symbol

Immediately after another creature's turn, Buer can expend a use to take one of the following actions. Buer can use 3 actions, and regains all expended uses at the start of each of her turns.

Attack. Buer makes an attack with Aegeria or Pneumousia.

Tentacle Bash. Constitution Saving Throw: DC 18, six creatures within 10 ft. Failure: 21 (6d6) Acid damage. Success: Half damage. Success or Failure: She can’t take this action again until the start of her next turn.

Frightful Presence. Buer casts Fear using the same ability as Spellcasting. She can’t take this action again until the start of her next turn.