Great Ming: I'm a Face Reader, and the Empress Forces Me to Marry Her from the Start

A young sorcerer fallen on hard times is living on the streets, nearly starving to death. On a whim, he tells the Empress her fortune and predicts she will suffer a bloody disaster within three days. The Empress draws her sword. "If your prediction is right, I'll make you Imperial Preceptor. If it's wrong, your entire family will be executed!" Three days later, assassins from an enemy nation launch a night raid on the palace... I counter with a single protective talisman, and change the fate of the world.