I think the demon king is the most interesting without a doubt. He has a complex personality. On one hand, he has his old, powerful self with all the pride and abilities of a demon king. On the other hand, he's trying to fit into the human world, learning about things like money, work ethics, and social norms. His female co - worker is also interesting. She slowly discovers the truth about him and their relationship evolves in a unique way throughout the story.
There's also the hero from the devil's world who comes to the human world to find the devil. His character is interesting as he has to adapt to the human world as well, but with a different set of motives compared to the devil. He has this sense of justice from his world which clashes and also meshes with the new environment he finds himself in.
The devil himself, Satan Jacob, is very interesting. His transformation from a powerful, feared devil in his own world to a part - timer in a fast - food joint in the human world is quite a comical and engaging change.
The novel often explores the idea of identity. The demon king is no longer just a fearsome ruler but also a normal - ish guy working a part - time job. There's also a sense of humor in the story, which is kind of a theme in itself. It uses the absurd situation of a demon king being a part - timer to create comical moments and situations.
Lucifer himself is often very popular. Fans like to explore his complex personality, his struggle between his devilish nature and his new life in the human world.
The protagonist stands out as a very interesting character. He has to deal with the expectations and prejudices of others while trying to find his place again. The mysterious transfer student is also quite interesting. Her sudden appearance and her hidden motives keep the readers guessing. And the old - time rival of the protagonist from his demon king days, who now has a new role in the academy, is a character full of complexity and intrigue.
The main character is the devil, of course. He is the central figure who has to navigate the human world in his part - time job.
The most interesting part could be how the timer acts as a catalyst for their meetings. For example, if in a busy city, two people's paths cross every time a certain timer goes off. It gives a sense of fate and destiny, as if time itself is conspiring to bring them together.
Anos Voldigoad is definitely one of the most interesting. He has such a powerful presence and his nonchalant attitude towards many things is both amusing and intimidating. Misha Necron is also interesting. Her relationship with Anos and her own growth throughout the story add depth to the narrative.
The main character, the misfit demon king himself, is quite interesting. His struggle to fit into the new academy while having the memories and power of his past self makes him stand out. Another interesting character could be his rival in the academy who constantly challenges him.
Maou's underling, Alciel, is also an important character. He is loyal to Satan and tries to help him in the human world, often getting into funny situations while doing so.