Turns Out I'm the Real Monster?!

Working as a lowly enforcer for the imperial court, Jiang Mu’s career plan was incredibly simple— By day, he’d go out hunting monsters to grind achievement points, striving for a meteoric rise into the high court; By night, he’d go home to cuddle his wife, striving to have a chubby baby boy. But as he kept slaying and slaying, he suddenly realized something was terribly wrong… Holy crap, it turns out I’m the real demon!!! And what’s even more outrageous… the random wife he picked up is actually the reigning Empress?! — Description from novelcodex.org