My Junior Brother Is the World-Destroying Boss [Book Transmigration]

I transmigrated into a book and became the most beloved and admired senior disciple at Cloudpeak Academy. Then a stubborn little junior brother with a useless spiritual root transferred in. He's destined to become the world-destroying final boss who tears the Immortal Emperor apart with his bare hands. And my mission is to act like his devoted lackey, get close to him, then take his life. Damn it. Theme: Reforming the antagonist and growing together