Multiattack

The emperor's hyena makes two bite attacks.

Bite

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage plus 10 (3d6) necrotic damage.

Black Breath (Recharge 5-6)

The emperor's hyena breathes a 15-foot cone of noxious black vapor. Each creature in the area that isn't an undead or a construct must make a DC 12 Constitution saving throw, taking 14 (4d6) necrotic damage on a failed save, or half as much damage on a successful one. If the saving throw fails by 5 or more, the creature gains one level of exhaustion. This exhaustion lasts until the creature finishes a short or long rest.