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

Multiattack. The blood hound makes two Rending Bite attacks.

Rending Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) piercing damage, plus 22 (4d10) necrotic damage if the target is frightened. This attack ignores damage resistance.

Abyssal Howl (Recharge 4–6). The blood hound emits a deep guttural howl in a 60-foot cone. Each creature in that area must succeed on a DC 12 Wisdom saving throw or take 16 (3d10) psychic damage and be frightened until the end of the hound's next turn. While a creature is frightened in this way, its speed is halved, and it is incapacitated. A target that successfully saves is immune to the Abyssal Howl of all hounds for the next 24 hours.