Itto Rasetsu 1 Volume 3

"Ittou Shura, which spent everything of oneself in one minute, didn't win against Raikiri. Kurogane himself understood that. So that guy, he spent everything himself in one sword swing instead of one minute! With astounding concentration, he concentrated his 'strongest single minute', and magnified his physical strength in a many-fold leap, and added swing speed and power…!"

Compared to burning his stamina using the usual Ittou Shura to run forward, Ikki had spent the stamina of running a hundred meters at the first step instead just then. That was entirely beyond the domain of humans. It was not the realm of a man who fell into the realm of the shura. Exceeding limits beyond limits. A… demon that exceeded humanity. If it needed a name―


Ittou Rasetsu[3].