Well, a frequent theme is the transformation of Naruto's character. He goes from the regular Naruto we know to a demon lord, and this change often explores his darker side. Also, there's the theme of conflict. There could be conflict between Naruto and the other ninja villages as they see him as a threat. Additionally, some fanfictions focus on the theme of identity, as Naruto has to figure out who he is now that he's a demon lord.
Common themes include the exploration of a different power hierarchy. As a demon lord, Naruto is at the top of a new power structure, and how he manages that is often explored. Another theme is the blurring of good and evil. Just because he's a demon lord doesn't mean he's completely evil, and this is often a central idea in these fanfictions. Also, the theme of destiny comes up, as Naruto may be on a different path than the one he was originally on, and how he deals with this new destiny is an important aspect.
One common theme is power and its corruption. Naruto as a demon lord might struggle with the new - found power and how it affects his relationships. Another theme is the idea of redemption. Despite being a demon lord, he may still strive to do good or atone for his actions. And there's also the theme of isolation, as being a demon lord may set him apart from his former friends and allies.
Power is a common theme. The demon lord usually has great power, and the fem kyuu in the harem may be drawn to that power or gain power through their association with him.
Power struggle is a common theme. Naruto as a crime lord would constantly face challenges from other criminal groups or even the ninja villages. Another theme could be redemption. Even as a crime lord, he might still have some good in him and strive to atone for his actions. And secrecy, since he has to hide his true identity and motives from his former friends and allies.
One common theme is power corruption. Since Naruto is a powerful character, in these fanfictions, his transformation into a 'dark lord' often involves him being corrupted by his own power. Another theme is the breakdown of relationships. His friendships and bonds with others are usually shattered as he turns to the dark side. Also, there is often a theme of a new world order. Naruto, as the 'dark lord', tries to reshape the ninja world according to his new, darker ideals.
Power is a common theme. Since the Raging Demon is a very powerful technique, many fanfictions focus on how characters gain, control, or are corrupted by this power. Another theme is heritage. The Raging Demon often has roots in the history of certain clans or ninja arts, so stories explore the connection between the present characters and their ancestors in relation to this technique.
A common theme is the power struggle. Since demons usually have strong powers, there's often a struggle between Naruto and his demon mate in terms of who is in control or how to use their combined powers. Another theme is acceptance. Naruto has to accept the presence of this demon mate which is different from his normal relationships. And there's also the theme of loyalty. The demon mate and Naruto often develop a deep loyalty towards each other as they face various challenges together.
One common theme is the struggle for acceptance. The demon brothers often face prejudice in the Naruto world because of their nature, so a lot of fanfictions focus on their journey to be accepted. Another theme is power and its control. They usually have great power, and the stories may revolve around how they learn to control it.
Power struggle is a common theme. Characters with demon bloodlines often face internal and external battles to control their powers. Another theme is acceptance. They need to accept their unique bloodline and the responsibilities that come with it.
A common theme is power. The combination of Naruto's existing powers and the added demon - related powers often leads to a new level of strength. Another theme is identity. Naruto has to figure out how being associated with a demon affects who he is. For example, in some fanfictions, he might struggle with being seen as a monster because of the demon connection.
One common theme is the struggle with identity. Since Naruto has half - demon blood, he has to figure out who he really is, whether he's more human or more demon. Another theme is power. The half - demon aspect usually gives him some unique powers, and he has to learn to control them.
One common theme is power. The Kitsune demon often brings new and powerful abilities to Naruto or the characters involved. Another theme is the idea of a hidden or mysterious past. Since Kitsune have a rich lore, it's often used to add depth to the Naruto world's backstory.