[I traveled through time and became a "cannon fodder maid", but picked up the "Emperor Experience Card"]
The Sasou girl who was about to be killed with a stick in the first chapter found an "Emperor Experience Card (7 days)" before she died. I went online overnight. I was an emperor during the day and a maid at night. I used the imperial title to promote myself to a noble concubine, grant immunity from death, and kill villains. The card was about to expire on the seventh day, but the real emperor came back and smiled at me: "Is it fun? I am the card holder."