Forbidden love is also typical. Society or the natural order in the story's world may not accept the relationship between a demon king and a non - demon. This creates a lot of tension and drama in the story. It's like Romeo and Juliet, but with a demon king twist.
One common theme is redemption. The demon king, after a life of doing evil, now tries to make up for his past mistakes. For example, in many novels, he might help the weak or fight against other evil forces that are a threat to the world he now wants to protect.
One common theme is the forbidden love. Since demons are often seen as dark and dangerous in most mythologies, a relationship with a demon is considered taboo. Another theme is redemption. The demon character may be on a journey of self - redemption through love. For example, in some novels, the demon may be trying to break free from its evil nature because of the love it has for the human or other non - demon character.
Isolation can be another theme. Despite their power, demon kings may be alone or have very few they can truly trust. They might be feared and shunned by most of the world in the story, which can lead to their own internal struggles and character development.
The theme of change is also prevalent. His entire lifestyle, values, and relationships change. He might go from being feared to being respected or befriended. There is also often a theme of secrecy. He has to keep his past a secret in some cases, which adds an element of suspense to the story. He may struggle with when and how to reveal his true identity, especially when he starts to care about the people in his new life.
Power struggle is a common theme. Usually, the demon king girl has to deal with various forces that either oppose or try to use her power. For example, in many stories, there are other kingdoms or powerful entities that see the demon king girl as a threat.
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.
Power management is a common theme. The demon king often has to figure out how to use his power effectively in a more practical sense, not just for destruction.
Power is a common theme. The demon king usually has great power, and the story often revolves around how he uses or loses it. For example, in some novels, the demon king might be trying to gain more power to rule over different realms.
One common theme is forbidden love. Since demons are often seen as different or dangerous in the context of human society, the relationship between a demon and a human is usually frowned upon. For example, in many stories, there are social or cultural barriers that the couple has to overcome.
One common theme is the struggle between good and evil. Since angels are often seen as the representatives of good and demons as bad, the romance between them challenges this simple dichotomy. For example, in some novels, a demon may have a kind heart deep down.