Power. Usually, the reincarnated demon king has some form of great power from their past life that they can tap into. This power often makes them stand out in the new world they are in.
Sure. 'The Eminence in Shadow' is a great one. It features a character who has the idea of being like a demon king reincarnated. The story is full of interesting twists and turns as he builds his own 'shadow' organization while hiding his true intentions.
Power and growth are common themes. When a character is reincarnated as a demon or in a world with demons, they often have to gain power to survive. For example, in 'That Time I Got Reincarnated as a Slime', the slime protagonist gradually becomes stronger. Another theme is identity. The reincarnated character may struggle with their new demonic identity or how they fit into the world of demons.
I'm not entirely sure about its popularity. It might be popular among certain niche groups who are into dark fantasy or demon - related stories. There could be a dedicated fan base that enjoys the unique elements and plotlines it offers.
It depends. Some fans of the fantasy and isekai genres might find it very popular. It often has elements like a powerful demon king getting a second chance at life, which can be really appealing to those who enjoy such storylines.
According to the information provided, I recommend the fantasy sword and magic novel,"The Thousand Year Battle of the Demon God". Although the male protagonist doesn't use a spear, as the reincarnation of the Demon King, he has an intense confrontation and battle plot with the Radiant King, which fits the plot you mentioned. I hope you like my recommendation. Muah ~
Sure. 'Overlord' is a great one. It involves the story of a powerful being being reincarnated in a game - like world filled with various races and magic. Another is 'Re:Zero − Starting Life in Another World'. Although it's not strictly about a demon reincarnation, it has elements of reincarnation and a dark, complex world with some demon - like characters. There's also 'That Time I Got Reincarnated as a Slime', where the protagonist is reincarnated as a slime in a fantasy world with demons and other races.
Well, in a 'demon king mismatched light novel', it might be about a demon king who is out of place in his or her world. Maybe the demon king has powers that don't fit the normal expectations of a demon king in that particular fictional universe. It could also be about the demon king's relationships that are mismatched, for example, befriending those who should be enemies according to the norms of the world.
Yes, it's definitely worth reading. The story often has unique world - building. It takes you into a fantasy realm filled with magic and interesting characters. There are often complex relationships between the summoned characters and the demon king, which makes for an engaging plot.
Often in these types of light novels, the 'Incomparable Demon King' might start from a position of great strength but face new challenges that force him to grow or change. It could be that a new threat emerges that he has to deal with, or there are internal struggles within his own domain. There might be a love interest or some sort of relationship that develops and affects his actions and decisions as well.