Nigoru Hitomi de Nani wo Negau: Highserk Senki

One day, Takakura Yorizo, an ordinary office worker, died of a myocardial infarction. However, he was given a second life in another world. Not as a reincarnated person endowed with powerful skills, but as a soldier in the Hyserk Empire, a small nation surrounded by great powers. Thrown onto the front lines of the war under the new name of Walm, he and his comrades fight their way to the brink of death, despite being covered in the indelible blood and stench of death. A party of adventurers wielding powerful magic, and teleported warriors hailed as "heroes" who burn everything to ashes with overwhelming force. In the midst of these life-or-death battles, Walm's talent as a warrior, which would never have been awakened in peacetime, gradually begins to blossom. With his eyes clouded with darkness... The unique war tale begins in style.

(Source: Official Site, translated)