Kimi to Boku no Saigo no Senjou, Aruiwa Sekai ga Hajimaru Seisen

In a world forever scarred by ancient wars and the emergence of fearsome demons, humanity is split between two rival nations: the magically-inclined Empire and the technologically advanced Sovereign Union. For generations, their conflict has raged, fueled by mutual distrust and the deep-seated belief that the other side harbors true evil. Yet, amidst this perpetual strife, a glimmer of something unexpected emerges. When a young, exceptionally skilled Imperial knight and a formidable princess from the Sovereign Union cross paths on the battlefield, their initial clash ignites a curiosity that transcends their nations' animosity. As they navigate the complexities of their respective duties and the ever-present threat of war, a peculiar bond begins to form, challenging everything they thought they knew about their enemies and, perhaps, the very nature of their divided world.

✦ AI-drafted summary