Mutsu Enmei Ryuu Iikai-den - Shura no Mon - Mutsu-san wa Chou Tsuyoi?!

Even after being reincarnated into a world where magic is everything, the "Mutsu Enmei-ryu" remains undefeated. A half-naked man descends into an alternate world... This man has no magical powers and no memories, but he's incredibly strong in battle! During the battle, the man remembers his own name... it's "Mutsu"!