There might also be a theme of self - discovery within the context of being an overlord. The character may start to question their values and motives as they gain more power and influence in the world of the novel.
The titular worldly overlord is of course a central character. This is usually a strong - willed individual with great ambition.
Another theme is leadership. As an overlord, Percy has to lead. Fanfictions might show his decision - making processes, like how he deals with rebellions or manages resources. It's all about how he steps up to the leadership role.
One common theme is power struggle. Clementine often finds herself in situations where she has to either gain power or fight against those with more power in the Overlord universe.
Survival is also a big theme. The characters in both Naruto and Overlord often find themselves in dangerous situations. In fanfiction, this can be intensified as the characters from one series are thrown into the other's world and have to adapt and survive in a completely new and often hostile environment.
Power is a common theme. Many fanfictions explore how the characters gain and use power, like in 'Ainz's Ascent' where it shows his journey to greater power.
Often, there are themes related to loyalty and betrayal. In a Yuri relationship in 'Overlord' fanfics, the loyalty between the two female characters can be tested. This could be due to external factors like the politics or battles in the 'Overlord' world. And when one character feels betrayed by the other, it can lead to a lot of drama and emotional turmoil, which makes for an interesting read.
One common theme is the exploration of Shalltear's power. Since she's a very powerful character in the Overlord universe, many fanfictions like to test her limits when she's in a crossover situation. Another theme is loyalty. Shalltear's loyalty to Ainz is a big part of her character, and in crossovers, this loyalty often gets challenged or reaffirmed in different ways. For example, in some crossovers, she has to choose between following Ainz's commands and doing what she believes is right in the new world she's in.
Rebellion against the status quo can also be a theme. As an overlord, fem Harry may not conform to the traditional rules and hierarchies. She might break the old ways and establish her own, which can lead to conflicts with existing powers in the story.
Another common theme is isolation. When Naruto becomes so powerful, he may find it hard to relate to his friends and comrades in the same way as before. He might be on a different level both in terms of power and understanding, which can lead to a sense of isolation. However, he usually tries to bridge that gap. And also, the theme of changing the ninja world order is common. His new status gives him the ability to influence and reshape the existing power structures in the shinobi world.
Power and responsibility is also a theme. Just like in the original Spider - Man stories, in the fanfiction set in the Overlord universe, Spider - Man has to figure out how to use his powers in a world that might not have the same moral compass as his own. He has to decide when to step in and when to hold back.