"Beast † Blood" is a manga series that blends elements of supernatural horror, action, and psychological drama. The narrative centers on a world where humans coexist with monstrous entities known as "Beasts," which are born from human desires and emotions. These Beasts are both feared and hunted, as they possess immense power and often wreak havoc on society. The story primarily follows Kuga, a young man who becomes entangled in the conflict between humans and Beasts after a tragic encounter leaves him with a cursed power. This power allows him to transform into a Beast-like entity, granting him extraordinary abilities but also threatening to consume his humanity.

Kuga's journey is driven by a desire for revenge against the Beasts that destroyed his life, but as he delves deeper into the world of Beasts and their origins, he uncovers unsettling truths about their connection to humanity. Along the way, he encounters a diverse cast of characters, including other individuals who have been affected by Beasts, hunters who specialize in exterminating them, and enigmatic figures who manipulate both sides for their own agendas. The narrative explores themes of identity, morality, and the blurred line between human and monster, as Kuga struggles to maintain his humanity while wielding the very power he despises.

The plot is structured around episodic confrontations with various Beasts, each representing different facets of human desire and emotion, such as greed, rage, or despair. These encounters serve as both action-driven set pieces and opportunities for character development, as Kuga and his allies confront their own inner demons. The series also delves into the larger societal implications of the Beasts' existence, examining how fear and prejudice shape human behavior and institutions. As the story progresses, Kuga's quest for vengeance becomes increasingly complicated by his growing understanding of the Beasts and his own transformation, leading to a climactic confrontation that challenges his beliefs and forces him to make difficult choices.