What Do You Wish For With Those Murky Eyes: Record Of Highserk War summary:

One day, Raizou ​​Takakura, an average salaryman, had a heart attack and his life ended that day. But, he got a second life in a different world.Reincarnated with strong skills― wasn't happened to him, instead, he was reincarnated as a foot soldier in a small country, Highserk Empire, which is surrounded by large countries. With a new name, Walm, he was thrown into the frontlines of a war. Covered in blood and stench of death, along his comrades, he was slipping through the life-or-death situations.An adventurer party with members who could use powerful magic, transferees with overwhelming power called the "heroes." In a deadly battle with them, Walm gradually developed his talent as a warrior which would've never awaken if he were to stay in times of peace. While his eyes becoming dark and muddy over time.Web Novel (Japanese): https://ncode.syosetu.com/n6680gq