Armor Class 13
Hit Points 58 (9d8 + 18)
Speed 30 ft.
Saving Throws STR +5, CON +4, CHA +4
Damage Resistances cold
Damage Immunities fire, poison
Condition Immunities frightened, poisoned
Senses Darkvision 120 ft. (unimpeded by magical {@variantrule Darkness|XPHB}), passive Perception 10
Languages Infernal; telepathy 120 ft.
Challenge 3
Magic Resistance. The devil has Advantage on saving throws against spells and other magical effects.
Multiattack. The devil makes one Beard attack and one Infernal Glaive attack.
Beard. m +5, reach 5 ft. Hit: 7 (1d8 + 3) Piercing damage, and the target has the Poisoned condition until the start of the devil's next turn. Until this poison ends, the target can't regain Hit Points.
Infernal Glaive. m +5, reach 10 ft. Hit: 8 (1d10 + 3) Slashing damage. If the target is a creature and doesn't already have an infernal wound, it is subjected to the following effect. con DC 12. The target receives an infernal wound. While wounded, the target loses 5 (1d10) Hit Points at the start of each of its turns. The wound closes after 1 minute, after a spell restores Hit Points to the target, or after the target or a creature within 5 feet of it takes an action to stanch the wound, doing so by succeeding on a DC 12 Wisdom (Medicine) check.
Monster Manual (2024), p. 33