Satan Jacob

Sadao Maou / Satan Jacob is the main protagonist of the series. He was once the Demon King who declared war on Ente Isla in an attempt to annex the four continents. However due to the actions of the Hero Emilia Justina and her companions he was forced to retreat to Earth causing him to lose almost all of his powers. Satan was wellknown throughout Ente Isla as the great overlord of his people his name synonymous with the terror and cruelty his army brought to those unfortunate enough to fall victim. He allowed his minions the right to perform any heinous acts they deemed fit showing immense cruelty through the slaughter of many innocent humans in his conquest. By contrast on Earth Sadao Maou is shown to be a diligent and proactive employee instead applying his strong drive and determination to better himself in his new life. Forced to spend time living as a human and interacting with those he previously considered to be lesser beings he has since developed a kindhearted and cheerful disposition making him popular among both his colleagues and neighbors. He now strives to climb the corporate ladder at MgRonalds. Source: Hataraku Maousama Wikia edited