Breathing Techniques in SAO

(Sword Art Online + Demon Slayer fanfiction)

As a transmigrator without any cheat codes, Tomioka Akemi was a little panicked when he found the breathing technique notes left by his ancestors. But when he thought that it was already 2022, how could there still be demons? He calmed down, until he heard about the SAO closed beta test...

"Hmm, this doesn't make sense. Why are Breathing Techniques and Sword Art Online in the same world?"

(Single female lead, Asuna, tentative storyline is Sword Art Online ---- Fairy Dance ---- Demon Slayer)