Love and romance can also be common themes. Characters in the fanfiction might fall in love, and their relationships can be a central part of the story. It could be a love story between two 'others' or between an 'other' and a normal character. This can bring out different emotions and development in the plot.
One common theme could be a corruption arc for Sans. Maybe something in the story causes him to lose his usual moral compass. Another theme might be a misinterpretation of his powers, leading him to accidentally hurt others at first. And sometimes, it could be a darker take on the 'kill or be killed' concept in the Undertale universe, where Sans is forced to take actions that harm others to protect himself or someone else.
It usually builds on the existing world and characters of the original work. It can offer new perspectives or alternate storylines.
Well, in 'boogiepop and others light novel', the themes of mystery and the unknown play a significant role. The plot is filled with elements that keep readers guessing. Also, friendship and the power of human connection are likely themes. Characters may rely on their relationships with others to face the strange and often dangerous situations in the story.
Another theme is the power of friendship. Their initial friendship is a strong foundation, and many fanfictions build on this, showing how their friendship evolves into a deeper, more passionate love, and how that friendship helps them face the challenges that come their way.
One common theme is the struggle between heroism and normal life. Spider - Son often has to balance being a hero and dealing with school, family, etc. For example, in many fanfictions, he misses important family events because he's out fighting crime.
Another theme is redemption. Edgeworth has a past that he sometimes feels he needs to atone for, and in fanfiction, Wright is often there to help him through that. It's like in 'The Path to Forgiveness' where Wright helps Edgeworth come to terms with his past mistakes.
Transformation is a big theme. How the character changes physically and emotionally when they turn into a werewolf is often explored. Also, the concept of the moon is very common. Since werewolves are often associated with the moon, many fanfictions use the moon as a symbol for power, change, or even as a trigger for the werewolf's transformation. There's also the theme of the werewolf's inner struggle, like trying to control their animal instincts in a human world.
One common theme is love against all odds. Often, the two characters face many obstacles in their relationship, but their love prevails.
Love is a very common theme. Most fanfictions focus on the romantic relationship between Bright and Win, showing their love in different ways.
One common theme is leadership. Since Ashe is a leader in her own right, many fanfictions explore how she manages her people and makes difficult decisions. Another theme is friendship and alliances. Ashe often has to rely on others, so stories about her making friends or forming alliances are popular. Adventure is also a common theme as Ashe goes on quests and battles enemies.