My Instant Death Ability Is So Overpowered, No One in This Other World Stands a Chance Against Me! Volume 6 by Tsuyoshi Fujitaka

With the majority of their class and the entire capital wiped out, Yogiri and Tomochika left behind the Kingdom of Manii in search of additional Philosopher’s Stones, the energy sources they were told to gather if they ever want to make it back home. Having received one stone from the Sage Sion, a second from Risley, and having taken a third from the self-styled War God Raiza, the pair next set their eyes on a new country in the east, following a lead on the potential location of another Sage. With the half-demons they were assisting now comfortably settled in the City of the War God, the two have left their previous companions behind to begin their journey home. But of course, nothing is ever simple. One after another, strange new people begin appearing in their path to block their progress, and some of their former companions may not yet be willing to let them go...