In the imperial era, swordsmanship was paramount, those with high levels of swordsmanship would become figures to be feared and admired. 'Kanaga Yashu' is known as a swordsman at a very young age, his black sword is capable of shedding thousands of thousands of liters of blood alone. He is also known as a demon sword user. Every high-level mission was always completed perfectly, and for that great achievement, the empire even appointed him as one of the generals. But in a major war that occurred in the southern continent, Yashu and all his troops were declared dead. Yes, that was almost completely true, but he was still alive, just alone, while his 5 thousand elite troops had died due to poisoning. 3 years passed, and Yashu reappeared in his clan, but a very different appearance made him unrecognizable by anyone, even always considered crazy and despised. Yashu accepts everything within limits, he doesn't want anyone to know his true identity, only for one main goal, revenge and to transform into the strongest samurai in the world.