(Fight ten yanderes, ten no systems, ten no golden fingers)
Roosevelt, who fell to the lower world and became the Demon King, was sealed for 1,000 years. With the help of Happy, he found a feather of the Demon King and revived the Demon King. However, he found that he was only level 1 and his subordinates were miserable. Roosevelt led the Demon King's army to invade the human world and retrieve all the feathers to regain his strength.
But in the process, Happy saw more and more women around the Demon King, and her hidden desire for control and possessiveness gradually exploded...
