Mythical Era: My Evolution Into A Celestial Beast (lightnovel.to)

A colossal Kun soars unscathed through missile fire, and a serpent thousands of meters long levels Australian cities before nuclear strikes drive it off. Amid this monstrous new world, Chen Chu gains the avatar of a palm-sized six-horned salamander, unsure what use it could be. But the creature evolves endlessly, grow…