Armor Class 18 (natural armor)
Hit Points 133 (14d10 + 56)
Speed 30 ft., fly 60 ft.
Saving Throws CON +8, WIS +7
Skills Arcana +6, Deception +9, Perception +7, Persuasion +9
Damage Resistances cold, necrotic
Damage Immunities poison
Condition Immunities poisoned
Senses darkvision 120 ft., passive Perception 17
Languages Abyssal, Common, Infernal
Challenge 11
Aura of Nightmares. Undead creatures within 30 feet of the shepherd gain a +5 bonus to attack and damage rolls. When any other creature that isn't undead or a construct starts its turn within 30 feet of the shepherd, that creature must succeed on a DC 17 Wisdom saving throw or take 11 (2d10) psychic damage.
Magic Resistance. The shepherd has advantage on saving throws against spells and other magical effects.
Multiattack. The shepherd makes two attacks: one with its claws and one with its staff.
Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage plus 16 (3d10) necrotic damage.
Staff. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage, or 13 (2d8 + 4) bludgeoning damage if used with two hands, plus 26 (4d12) psychic damage.
Herd the Underworld (Recharges after a Short or Long Rest). The shepherd pulls twisted souls from the Underworld; 1d6 shadows (without Sunlight Weakness) arise in unoccupied spaces within 20 feet of the shepherd. The shadows act right after the shepherd on the same initiative count and fight until they're destroyed. They disappear when the shepherd dies.
Mythic Odysseys of Theros, p. 221