Isekai Cheat Magician (S01E12)

The sorrowful tale of the "Bloody Rhapsody," the most devastating battle in history, is poised to repeat itself. Dark sorcery has transformed soldiers into frenzied berserkers, unable to tell allies from enemies, as both forces march toward the royal capital, ready to unleash chaos. Confronted by an overwhelming number of these wild warriors, Taichi faces a critical choice. He ultimately decides to harness a power that far exceeds what one individual should wield, all in a desperate attempt to safeguard his loved ones, but the consequences of his decision loom large.