Valkyrie no Kiko

Seven years ago, humanity was thrust into a hidden war for its very survival against an otherworldly threat of divine beings. In the desperate struggle to protect mankind, a young girl named Waka and her companions were chosen by the gods to become Valkyries. Bearing the immense weight of this sacred duty, they sacrificed their lives to bring the devastating conflict to a definitive end, securing peace at the ultimate cost. In the aftermath of that secret war, Waka’s younger sister, Kiko, has spent her life growing up in a world unaware of the price paid for its safety. Now entering high school, she attempts to navigate the ordinary challenges of adolescence while living in the shadow of her sister's forgotten heroism. However, the fragile tranquility of the past seven years is suddenly shattered when the divine beings mysteriously return. With the original Valkyries gone and the looming threat once again descending upon humanity, Kiko finds herself standing at the precipice of a renewed conflict, forced to confront the same celestial forces that claimed her sister's life.