In the reinforced concrete city, Sanzo, a Bangladeshi immigrant, is both quiet and mysterious. However, his life changed drastically in an accident. Sanzo becomes a vampire, and not only that, he becomes the personal assistant of Marianne, a thousand-year-old vampire who is also the CEO of a charity organization. In this world of vampires and violence, Sanzo finds himself embroiled in supernatural events. His quiet life is shattered and replaced by an exploration of the unknown and deadly dangers. As the truth behind the charity is revealed, Sanzo is forced to face the Church of Light, an extremist group that believes the organization violates God's will. He becomes the intersection of two worlds, caught between good and evil. When the Church of Light launches a violent attack, Sanzo reveals his hidden fighting skills, shocking Marianne. This also earned him a reputation as the company's defender. However, this newfound ability sparked fears within the company. Sanzang's mysterious past becomes the focus of the company, and his deadly abilities raise more doubts in this gray area. As time passes, Sanzo's past comes to light, creating another threat. This time, Marianne must choose between his goodness and his violence. Can she see Sanzo's true self, or are they destined to go their separate ways in the chaotic world of vampires? "Bloodline: The Gray Rhythm Behind the Night" is a captivating novel that reveals the complexities of human nature and explores the entanglement between the supernatural and human nature. In this world, the twilight zone between good and evil, and the desire for compassion and violence will lead readers on a twisting adventure.