Ryomen Sukuna was the result of a misfortune between a human and a vampire. He wasn't the first hybrid in history, but few of they were born. It all begins with his mother, Honoka Ryomen, on one of his trips to Europe in the 19th century, after Japan's isolation from the rest of the world. She had escaped her homeland after the man she married poisoned her family and her newborn daughter. In great sorrow and fear, she remained hidden in a small town in Germany, hoping to be safe and as far away from the perpetrator as possible.

Out one night, she found herself caught in the middle of an attack by a vampire. He caught her unaware in the empty streets, biting her, and in the process, filling her womb with his poisonous seed in a horribly cruel subjugation in the shadows. The identity of her attacker soon became known: Gustav Hipperdinger, the King of the Vampires. He let his victim live so she could continue producing fresh blood. He wouldn't waste a fine oriental delicacy; she would be excellent as part of his human livestock to feed his clan and as his slave.

The following years were psychological torture for poor Honoka, as well as for her second son, Sukuna, in that den of toxicity. Sukuna's childhood was based on following strict house rules, relying on perfection, and not opening up emotionally. It would only reflect poorly on the clan. In itself, a hybrid living under the same roof as the Vampire King was a bad image, or worse. The little boy was seen as a dirty hybrid, a defective and unwanted offspring, who, if not for his mother, would have been eaten alive—words often repeated to him by Gustav's relatives.

In Sukuna's eyes, the leader was just an greatest asshole who played the role of an... asshole, just like the others in that house. His mother, the only solace he saw in that gloomy, dry, and desolate world, was what kept him distracted and calm, trying to find peace in her maternal warmth. Sadly, her life ended as soon as Sukuna turned 12. He never saw how his mother's life was taken away, nor did he know the reason; he only saw that poor, gaunt, and weak body lying on the dining room rug with tired eyes and that disheveled black hair covering part of her face. He only knows that the person responsible was his father.

As soon as the tall man left the room, the poor boy approached, sad and scared, crying over his mother's body, wishing she would come back to life so as not to leave him alone in that house full of evil people. Now, he would be an absolute target of the Hipperdinger clan, if only he could adapt and stay out of it.

Many decades later, as a young adult, with some experience based on his vampiric abilities, Ryomen would soon become renowned in his community for being the first to overthrow and kill the King of the Vampires, after a fierce fight that began at a mere provocation from Gustav, causing him to collapse emotionally. He demonstrated his dominance by savagely devouring his father in front of the rest of the clan, who were not so lucky when they were caught and eaten by the hybrid. Now, his hunger was no longer limited to blood, but rather to flesh.

In the world, vampires would disappear, becoming a very small group thanks to Sukuna's work. Vampire flesh was delicious to his tongue, and that part of him demanded he fill that void of hunger by killing his kind as punishment and revenge. None escaped his clutches, humans much less so; all would go into his stomach.

In the middle of summer, you were in the countryside, living next to some houses that could be seen in the distance. You were repairing things from your outdoor storage using dangerous tools, and by accident, you superficially cut your hand, causing the blood to flow rapidly. By chance, Sukuna was near the field among the vast grasslands, searching for food with his nose. You would be a good snack to cool off the heat.