Sadao Maou/ Satan Jacob is the main protagonist of the series. He was once the Devil 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 is a humanoid demon that stands over three meters tall, possessing a fair complexion, sharp red eyes, and slightly messy black hair with a mildly unkempt spiky appearance. His body is well-built with a muscular torso, thick neck, and toned arms and legs. Though his default form is humanoid in appearance, he possesses several features that are decidedly more demonic, including sharp-clawed hands, a pair of yellow ridged horns that curve outwards from beneath his hair along the sides of his head, and large furry goat-like legs ending in thick hooves. Satan also possesses two large bat-like wings that span several times the length of his body when unfurled, though he does not require them to fly, and usually keeps them hidden inside his body. His outfit as the ruler of demons consists of a dark jacket with a gold trim around the seams, the bottom partially opened to reveal his waist. He wears short black pants which are the same color as his top, the former of which are tucked into a pair of large dark boots that cover his animal-like calves and feet. Over his clothing he wears a high-collared cape in the same colors as his jacket, fastened at the front with a thin golden chain, and held in place by large shoulder-pads bearing a small resemblance to his horns. As a human, Maou has the appearance of an average Japanese young man. His facial features and hair are largely unchanged from his original demonic form, though he appears younger and his face more expressive than before. The most noticeable difference aside from losing his horns, hoofed legs, wings, and claws, is the drastic reduction in stature between his human and demon forms. As Sadao Maou, the Devil King is roughly the height of the average human, being noticeably shorter than before with a smaller build that lacks the musculature and imposing size of his previous body. While living in Japan, he normally wears simple clothing purchased from UniClo, a store specializing in low-budget, used clothing, his typical garb being a simple t-shirt and jeans. While working at MgRonald's, Maou dresses in the franchise's uniform consisting of a short-sleeved red t-shirt with a button-up collar, a yellow strip running across the mid-torso with the company's logo on the right breast. Also included is a pair of black pants, a belt, and a matching visor hat, also bearing the MgRonald's logo. When he regains his powers, Maou's body reverts back to its previous form, depending on the amount of magic he has accumulated. In the manga, when he regained his powers after the mall collapsed, only his stature remained human, but his pants were torn due to his transformed legs. In the anime, he returns to his full demon form and all his clothes were shredded. Perhaps the most intelligent and charismatic of his kind, the Devil King came from humble origins as a member of a low-class goblin tribe, yet through tireless efforts and a drive to better his people, managed to gain support from others, eventually uniting the warring factions of the Demon World under his rule. Satan was well-known throughout the lands of Ente Isla as the great overlord of his people, his name synonymous with terror and cruelty, despite being in truth a gentle leader who sought for less destruction and casualties as much as possible. His true intentions were misunderstood due to the fact that he ordered his generals to conquer the lands of Ente Isla without explaining the meaning of 'conquer', thus leading for each general to conquer in his own way leaving cruel actions and destruction in the Western and Southern Continents, staining his name with bloodshed. While his actions in life were for the betterment of demonkind, he had to conquer the human civilization to ensure the survival of the demon race. Later it is revealed that during the time of his invasion to Ente Isla, he decided rather than heading to battle, to instead research human society. He did this to gain information that could help him conquer Ente Isla, but also because he had a deep curiosity and respect for human society. During this time it is revealed that Satan actually did care for the humans he trampled during his invasion, but was forced to choose between humankind or the survival of the demon race, after which he ended up choosing the latter. Satan's true motivation was to create a situation in which he could force the human race into producing negative emotions toward demons, thus creating large amounts of demonic energy (which was starting to run out in the Demon Realm). He never intended to completely annihilate the human race, but to actually conquer it. He gave each of his generals free will on how to carry the conquest, but established that they must accept human's surrender. Due to this, though in some cases the conquest was gruesome and full of bloodshed (like in Malacoda's case), in other cases was relatively moderate, without actually damaging anyone but soldiers who opposed the conquest (such as in Adramelech and Alciel's case). As the great ruler of demons, he was shown to be a proud and resolute individual, though his defeat at the hands of the Hero Emilia and the sudden loss of his magic abilities on Earth left him with no choice but to abandon that pride and live the life of an ordinary human. 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, the Devil King slowly began to understand mankind, and has since developed a kindhearted and cheerful disposition making him popular among both his colleagues and neighbors. While he does not desire to cause trouble to the world that has treated him with nothing but kindness, Satan has not entirely lost his desire for power and influence, and instead strives to climb the corporate ladder at MgRonald's. His hope is to legally obtain influence and wealth on Earth that will allow him to amass new resources with which to return home to Ente Isla. Due to this wish, or in spite of it, Maou expresses great pride in his job as a fast-food employee, and pompously brags about the many promotions he will hopefully receive in the future, often much to the dismay of those around him. Maou is most impressed with the fundamentals of capitalism, as he sees the market economy on Earth as a model for his new ideal society back home. His current goal is to observe the system in Japan and establish a more civilized society in the Demon Realm, one where profit and trade can be used as a means to obtain power without unnecessary bloodshed. Notably, he still possesses a strong drive to rebuild the Devil's Army and has consciously toyed with the idea of finding replacements for deceased generals. Sadao Maou is also shown to be thoughtful, well-mannered, and empathetic towards those around him, and is willing to help others in any way possible if he is able. This new disposition clashes heavily with the merciless Devil King the people of Ente Isla thought he was, something that confuses the Hero Emilia when she first encounters him on Earth. Despite her having been the cause of his downfall and subsequent depowerment, Maou displays no hostility towards the hero, and even some pity upon learning that she had been stranded on Earth alone while chasing him through the Gate. Despite being archenemies back home, he displays great strength of character despite her hostility towards him, quietly accepting her accusations without objection, and even showing concern for Emi's well-being and that of others. Naturally, his kindness confuses those who knew him back in Ente Isla. When asked directly about his previous actions as the Devil King, Maou also expresses regret for having done so many horrible things. He reluctantly apologizes to the Hero, though he ruefully claims not to have understood humans before having been forced to live as one, and has come to acknowledge this ineptitude. While he does not intend to shirk responsibility for the deaths he had caused, Maou rarely discusses it unless directly confronted. While he often appears to be clueless, the former Devil King is shown to be highly intelligent, and is able to analyze each situation from a logical perspective while discerning the best course of action. This is first seen through his amassing of political power in the Demon Realm, eventually becoming its ruler, and later during his strategic conquest of Ente Isla. Upon arriving on Earth, he not only manages to deduce the best way to survive without magic, but also uses his intelligence to spot potential assassination plots from Ente Isla, while bettering himself in the work environment. Despite his impressive mind, Maou appears to be dense about matters regarding women. He is shown reacting awkwardly and somewhat confused by Chiho's confessions of love, although some of his comments make it sound like he does this intentionally for reasons not yet revealed. In both worlds, Maou looks out for his juniors and subordinates, and believes that any leader must take responsibility for the actions of those who serve under him, prompting him to cover for Chiho Sasaki when she makes mistakes at work while on duty at MgRonald's. This state of mind even extends to his interactions with Lucifer, who once severely damaged Shibuya in an attempt to kill the Devil King and the Hero. After putting an end of Lucifer's rampage, Satan chose to use his newly-restored powers to repair the city and even chose to hide Lucifer from the police. In doing so he accepted full responsibility for the situation even knowing that using up his magic to fix everything would render them unable to return to Ente Isla. Even as a human, Maou retains his flair for dramatic speeches and poses.