Demon Slayer: Using the System to Mass-Produce Breathing Styles and Reforge Two Worlds

Tanjiro: “Most of us only know two or three Breathing Styles, but you know a hundred, Ryu?” Ryu: “That's right! There's Demon Breathing, Steel Breathing, Titan Breathing, Sharingan Breathing... In theory, as long as demons don't go extinct, I can keep creating new ones forever!” Ryu, a former athlete who transmigrated into the world of Demon Slayer and was reborn in the pleasure district, awakens the [Breathing Style Wholesale System]! He'd planned to safely hunt demons for points, keep a low profile, grow steadily stronger, and quietly make it through life. But from the start, he runs straight into Akaza on a patrol during a lull, then has Daki block his way! Hunted by two Upper Ranks at once, he's plunged into hellish difficulty right from the start! After narrowly escaping with his life, Lin Yue just wants to find somewhere safe to hunt monsters and stockpile points, unlock a hundred Breathing Styles, and slowly sweep the world's evil demons away. But the more he tries to keep his head down, the more the chaotic age pushes him forward. Bizarre threats far beyond those in the original story, secret demons never before recorded, and layers upon layers of deadly traps come one after another. He'd wanted to keep his head down and live in peace, but the times leave him no choice. He can only grow stronger at breakneck speed and crush every powerful foe!