Good vs. evil is another theme. Demon gods are often seen as the 'evil' side, and the novels may show the struggle between them and the forces of good. For example, in some novels, heroes rise to oppose the tyranny of a demon god. And this creates a lot of action - packed and moral - exploring storylines.
The theme of mystery also runs through. Demon gods are often mysterious entities. Their origins, motives, and true forms are usually shrouded in mystery. This mystery adds an element of intrigue to the story, making readers eager to uncover more about these powerful beings.
Power is a common theme. Demon gods usually represent great power, so the pursuit, control, and consequences of power are often explored.
Another common theme is the struggle between good and evil. Even though it's a demon god, there can be elements of good in it, or it might be in conflict with other forces that are considered 'good' in the context of the novel. Also, themes of redemption or damnation can be present, depending on how the demon god's story progresses.
One common theme is power - up. Naruto usually gains some form of power related to the demon god, which makes him more powerful than in the original series. For example, he might get enhanced physical abilities or new jutsu. Another theme is the development of relationships. The harem aspect means there are multiple romantic or at least very close relationships that Naruto has to navigate.
A common theme is the power struggle. In Naruto fanfiction, characters often strive for more power, like Sasuke's journey. In Demon God fanfiction, it's about taming or using the power of the demon god. In Fairy Tail, the guild members are constantly trying to become stronger. Another theme is friendship. In Naruto, Naruto's bonds with his friends are crucial. In Fairy Tail, the guild is all about friendship. And in Demon God fanfiction, sometimes the main character forms alliances which are based on a form of friendship.
Power is a main theme. The demon god in the novel is often associated with great power, and the characters either strive for it or are in awe of it. Another theme is good vs. evil as the actions of the demon god can be seen as either malevolent or, in some interpretations, a necessary force. Also, there's the theme of destiny as characters' fates are intertwined with the legend of the demon god.
Often, they are extremely powerful. For example, they might possess superhuman strength, magical abilities far beyond normal characters. They are usually depicted as having a malevolent or at least a very self - interested nature.
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.
Love is also a frequent theme. There can be love stories between angels and humans or even between angels and demons in some cases. For example, in some novels, a demon may fall in love with an angel, which challenges the traditional view of their relationship and adds an interesting dynamic to the story. This love often has to overcome many obstacles due to their different natures.
Power is a common theme. The power of the god and the power of the slayer. Another is rebellion, as slaying a god is often an act of rebellion against the established order.
Well, in this type of novel, a typical theme is the struggle against the old order. Since the protagonist is newly reincarnated as a god, they may face opposition from the existing gods or celestial beings. And then there's the theme of creation. Gods are often associated with creating things, so the story may involve the main character using their divine powers to create new worlds or species. Another possible theme is the exploration of morality. As a god, the character has to decide what is right and wrong on a much grander scale.
Power is a very common theme. The god emperor usually wields absolute power and the story often explores how that power is used, abused or challenged.