Armor Class 22 (natural armor)
Hit Points 283 (21d12 + 147)
Speed 50 ft., fly 150 ft.
Saving Throws DEX +13, WIS +11, CHA +12
Damage Resistances cold, fire, [object Object]
Damage Immunities lightning, poison, thunder
Condition Immunities charmed, frightened, paralyzed, petrified, poisoned, prone, restrained
Senses blindsight 120 ft., passive Perception 15
Languages Auran
Challenge 18
Air Form. Yan-C-Bin can enter a hostile creature's space and stop there. He can move through a space as narrow as 1 inch wide without squeezing if air could pass through that space.
Empowered Attacks. Yan-C-Bin's slam attacks are treated as magical for the purpose of bypassing resistance and immunity to nonmagical attacks.
Legendary Resistance (3/Day). If Yan-C-Bin fails a saving throw, he can choose to succeed instead.
Magic Resistance. Yan-C-Bin has advantage on saving throws against spells and other magical effects.
Multiattack. Yan-C-Bin makes two slam attacks.
Slam. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) force damage plus 10 (3d6) lightning damage.
Thundercrack (Recharges after a Short or Long Rest). Yan-C-Bin unleashes a terrible thundercrack in a 100-foot-radius sphere centered on himself. All other creatures in the area must succeed on a DC 24 Constitution saving throw or take 31 (9d6) thunder damage and be deafened for 1 minute. On a successful save, a creature takes half as much damage and is deafened until the start of Yan-C-Bin's next turn.
Change Shape. Yan-C-Bin polymorphs into a Medium humanoid. While in polymorphed form, a swirling breeze surrounds him, his eyes are pale and cloudy, and he loses the Air Form trait. He can remain in polymorphed form for up to 1 hour. Reverting to his true form requires an action.
Summon Elementals (1/Day). Yan-C-Bin summons up to three air elementals and loses 30 hit points for each elemental he summons. Summoned elementals have maximum hit points, appear within 100 feet of Yan-C-Bin, and disappear if Yan-C-Bin is reduced to 0 hit points.
Peal of Thunder. Yan-C-Bin unleashes a peal of thunder that can be heard out to a range of 300 feet. Each creature within 30 feet of Yan-C-Bin takes 5 (1d10) thunder damage.
Teleport (Costs 2 Actions). Yan-C-Bin magically teleports up to 120 feet to an unoccupied space he can see. Anything Yan-C-Bin is wearing or carrying is teleported with him.
Suffocate (Costs 3 Actions). Yan-C-Bin steals the air of one breathing creature he can see within 60 feet of him. The target must make a DC 21 Constitution saving throw. On a failed save, the target drops to 0 hit points and is dying. On a successful save, the target can't breathe or speak until the start of its next turn.
PotA, p. 221