Kain awakens in a mystical realm following his death as a college student, discovering a world where warriors bond with spiritual creatures as combat partners. Armed with a System and steadfast allies, he pursues dominance in this fantastical landscape. Yet his path diverges from convention: the spiritual creatures within his reach prove peculiar and unconventional. As Kain navigates beast-taming in this strange new world, he must learn to harness the power of his unusual companions to carve his legend and conquer the challenges ahead.