Fantasy: I Became the Ancestor of the Royal Family

What? ! I actually became the ancestor of the royal family? ! Is this emperor's country going to be destroyed? ! "Ding, congratulations to the host, for activating the Rise of the Strongest Empire system!" "Start the main mission, unify the world, and become the strongest empire in the world!" "Start the side mission, repel the enemy country, and regain the lost territory!" How dare you invade my emperor's country, you are seeking death! With the system in hand, I have the world...