Demon Slayer: Devour the Demon King and Evolve Without Limit

Synopsis: What? I transmigrated into the world of Demon Slayer, became the Flame Hashira, and died alongside Upper Rank Three, Akaza?

Phew. After a moment of disorientation, Ma Xi woke up. It turned out everything that had just happened was a dream.

Only after oversleeping did Ma Xi remember his date with his girlfriend. He rushed out, only to be hit by a car and killed. After death, he really did transmigrate into the world of Demon Slayer, where he became a disciple of the Flame Hashira, Kyojuro Rengoku.

Ma Xi accepted his new life and learned Flame Breathing from Kyojuro Rengoku. He passed the Demon Slayer Corps selection and became a member. Unwilling to die at the hands of Upper Rank Three, he trained desperately and even developed an eleventh form of Flame Breathing of his own.

After mastering his training, Ma Xi headed to the home of the protagonist, Tanjiro. But by the time he arrived, Nezuko and the others had already been killed by Muzan Kibutsuji. Ma Xi was no match for Muzan Kibutsuji either, and after being injected with his blood, he became the Demon King and awakened the Demon King System. From then on, to take revenge on Muzan Kibutsuji and become human again, Ma Xi began training even harder.