Demon Slayer: From the Start, Sun Breathing

Kamado Ao opened his eyes amid the mountain of corpses and sea of blood at the Final Selection. A cold voice appeared in his mind:

Breathing Simulator activated

Water Breathing detected. Analyzing...

Analysis complete

Optimization plan generated. Execute?

Others relied on inherited techniques. He relied on data. Others trained hard for ten years. He evolved every time he cut down a demon.

Water Rhythm: Modified. Water Rhythm: Frost. Sun Breathing awakened.

By the time an Upper Rank stood before him, his Breathing Style had already evolved twenty-seven times.

When Muzan emerged from the shadows, the System's final function unlocked:

Self-Created Breathing Style, Final Form: Can fuse all analyzed Breathing Styles

Shinobu Kocho asked him, “What's the longest thing you've ever said in your life?”

He thought for a moment. “Finished cutting.”

“...That's it?”

“Next.”

A taciturn god of slaughter, one slash per kill. This book won't reason with you. It only talks with its blade.

This novel and its characters are entirely fictional. Any resemblance to actual people or events is purely coincidental. Please do not imitate.