Demon Slayer: My Brother is Both Upper Moon and Primordial Blade

What if your brother walked two impossible paths—demon lord and legendary swordsman? As a tsundere ghost navigating a world of sugar-coated tragedy, the protagonist must face a reality where family bonds transcend the line between human and monster. No romance, just raw emotion and bittersweet choices. A slow-burn tale of loyalty, sacrifice, and the weight of being caught between two worlds that should never collide.