Blood Frenzy

You touch a willing creature, sharpening its focus with the instincts of a killer. The creature has advantage to hit creatures that are bloodied (have fewer than half their maximum hit points). When there is a bloodied, hostile creature within 30 feet of the target of this spell, the target creature has disadvantage to attack creature’s that aren’t bloodied.

At Higher Levels. When you cast this spell using a slot of 3rd level or higher, you can affect one additional creature for each slot level above 2nd.