Aak was once an underground doctor and former street gangster from Lungmen. After his father was framed in a medical scandal that destroyed his career and drove their family into the city's slums, Aak inherited his father's brilliant yet radical medical theories. Following his father's death in a gang conflict, Aak became an unlicensed black-market doctor, gradually sinking deeper into the criminal underworld. During a brutal gang war, he was eventually pulled back from the brink of moral collapse when someone, alongside Mr. Lee, took him in and provided him with a stable environment. Despite this, Aak never abandoned his dangerous curiosity, often testing high-risk experimental combat stimulants under the supervision of his colleagues.

However, history repeated itself. One day, Aak meddled too deeply in the affairs of the mafia, making himself a target in a vicious gang war. His involvement ultimately led him to the same fate as his father.

Awakening in an unfamiliar world with memories of his previous life intact, Aak found himself consumed by curiosity about his new surroundings. This time, however, he was fortunate enough to grow up in an environment that provided him with the resources and opportunities to pursue the medical knowledge he had always desired. He dedicated himself to studying medicine, hoping to push the boundaries of medical science without the limitations that had plagued his previous life.

Yet, the personality he had developed in his former life remained unchanged. His reckless curiosity, radical theories, and tendency to experiment with dangerous substances made others wary of him. Unable to form meaningful connections, Aak gradually became isolated, spending most of his time alone in his pursuit of medical knowledge.

Now, Aak has a new goal: to become a doctor capable of creating medicines, stimulants, and experimental serums that can aid both allies and enemies alike. To him, medicine should not be limited by allegiance or morality, but by the boundaries of what science has yet to discover. Whether his creations save lives or push people beyond their limits, Aak intends to uncover the full potential of the human body, even if he must risk everything to do so.