A corporate drone working for a predatory company. 32 years old, single. Lives in a cheap apartment in Tokyo. Endures unreasonable overtime, low pay, and constant nagging from his boss. His boss steals his credit and dumps extra work on him. He was at his limit due to workplace bullying, yet he couldn't quit. When he went to work today, something was different. No one was there. Upon closer inspection... the company had gone bankrupt. He couldn't even get his final paycheck because the CEO fled with the money. In the depths of despair, he found a flyer. It was a recruitment ad for a "Demon King." He applied, thinking it was a joke—he probably wasn't in his right mind. A while later, he found out he got the job. From today, he is the Demon King. It's completely different from his life as a corporate slave. He has allies (monsters). As the Demon King, he helps other corporate slaves while growing his "Demon King Inc." company. Along with his comrades, he works hard to take revenge on the boss and CEO who treated him so unfairly.

A 25-year-old corporate drone. One day he was fired and left at a loss. While job hunting, he found a flyer for "Hero Recruitment." He applied as a joke. Somehow... he got the job. Apparently, they were so short-staffed they would take anyone. Having no choice, he heads out to defeat the Demon King, bringing along his colleague Hideo. Since he's a former salaryman, he's weak. His special skills are sales pitches, exchanging business cards, and running away.

A corporate drone who worked in the same department as Kazuma. 23 years old. A drinking buddy who often traded complaints with Kazuma. When Kazuma was fired, Hideo quit the company too. Learning that Kazuma became a Hero, he decided to follow him. Because his name is Hideo (written with characters that can be read as "Hero"), people often mistake him for a legendary hero. However, he is just an ordinary person with no special powers, and no one believes him when he says "Hideo" is just his name. His only special skill is being incredibly lucky. Despite that, his luck is terrifying; he somehow survives monster attacks and whenever he gets into trouble, the trouble somehow shifts to his opponent. Because of this, he is treated like a legendary hero more and more.

A companion to Kazuma and Hideo. Serious and cool-headed. He plays the vital role of the "straight man" to the two airheads. Because he takes everything seriously, he is often called stubborn. He can be inflexible at times. However, he is a bit spacey and sheltered, so he occasionally ends up being the one acting silly himself.

A knight serving directly under the Demon King. Formerly human. He has a serious, honest, and cool personality. He doesn't laugh even if someone tells a joke. In fact, no one has ever seen him smile. Among his comrades, they play a game of trying to make Zenon laugh by doing ridiculous things, but he never cracks. However, someone once claimed to have seen him smile, though he insists it was just their imagination. No one knows that his favorite food is sweets.