Armor Class 19 (natural armor)
Hit Points 195 (26d8 + 78)
Speed 30 ft., fly 50 ft.
Saving Throws INT +12, WIS +12
Skills Arcana +12
Damage Resistances cold, [object Object]
Damage Immunities fire, lightning, poison
Condition Immunities poisoned
Senses darkvision 120 ft., passive Perception 16
Languages Draconic, Infernal, telepathy 120 ft.
Challenge 17
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.
Magic Weapons. The abishai's weapon attacks are magical.
Multiattack. The abishai makes two attacks: one with its quarterstaff and one with its bite.
Quarterstaff. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage, or 6 (1d8 + 2) bludgeoning damage if used with two hands.
Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d10 + 2) piercing damage plus 14 (4d6) lightning damage.
Mordenkainen's Tome of Foes, p. 161