Demonic Fortitude. If damage reduces the demon to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage was radiant or from a critical hit. on a success, the demon drops to 1 HP instead.

Shapechanger. The demon can use its action to transform and appear like a regular human. He may also transform certain parts to human or demon as well for an action.

Blood Frenzy. The demon has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Multiattack. Two attacks with its claws.

Claws. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit.  (6d10+6)slashing

Summon Harpy. Summon 2 harpies.