Armor Class 18 (natural armor)
Hit Points 195 (26d8 + 78)
Speed 30 ft., fly 40 ft.
Saving Throws INT +8, CHA +9
Skills Deception +9, Insight +6, Perception +6, Persuasion +9
Damage Resistances cold, [object Object]
Damage Immunities fire, poison
Condition Immunities poisoned
Senses darkvision 120 ft., passive Perception 16
Languages Draconic, Infernal, telepathy 120 ft.
Challenge 15
Devil's Sight. Magical darkness doesn't impede the abishai's darkvision.
Magic Resistance. The abishai has advantage on saving throws against spells and other magical effects.
Multiattack. The abishai makes two Fiendish Claw attacks, or it makes one Fiendish Claw attack and uses Spellcasting.
Fiendish Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) force damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or take 16 (3d10) poison damage and become poisoned for 1 minute. The poisoned target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Mordenkainen Presents: Monsters of the Multiverse, p. 40