Viinasumisshon Moto Koroshiya de Youhei no Chuunen, Yuusha no Ansatsu o Irai Sare Isekai Tensei!

A former mercenary is reincarnated into a magical world where his skills will make him a threat to the so-called heroes of this new world.
Former mercenary Suzuki Takashi was one of the best in his field and was only stopped when he died from cancer. But his job as a sharpshooter isn’t over. The next time he opens his eyes, Takashi finds himself in a totally different world! Brought over because of his skills, he must also master the ancient martial art Shingu-ryu and newly acquired magic to face off with powerful foes—who happen to be other heroes!

[From Seven Seas Entertainment]