Another theme could be her own growth as a character. In the series, she has her own journey, and in fanfics, this can be expanded upon. For instance, she might have to deal with personal issues outside of her teaching role, like her past relationships or her family. And how she overcomes these things can be a major part of the fanfic. It gives the author a chance to delve deeper into her character than what was shown in the original series. This can make for some really engaging stories as readers get to see a different side of her.
There are probably some on Archive of Our Own as well. The great thing about AO3 is that it has a wide range of fanfics with different themes. In the case of Karasuma Irina fanfics, you might find some that are more centered around her character development, like how she becomes a better teacher or how she overcomes her own insecurities in the 'assassin classroom' world.
Ayanokoji Kiyotaka is one of the main characters. He is highly intelligent but often keeps his true abilities hidden. Then there's Horikita Suzune, who is ambitious and determined to succeed in the school's competitive environment.
Ayanokoji Kiyotaka is very interesting. He is highly intelligent but often hides his true abilities. His complex personality and his mysterious past make him a character full of intrigue. Then there's Horikita Suzune, a strong - willed girl who is determined to rise to the top through her own efforts.
Kiyotaka Ayanokoji is the central figure. He hides his true abilities and manipulates situations subtly. Suzune Horikita is a key character as well. She is determined to succeed in the school's competitive system. Then there's Kakeru Ryuuen, a more aggressive and intimidating character who often creates conflicts within the school environment.
One of the main characters is Lily. She is a key figure in the story, often involved in important spy operations. Another main character is the teacher who trains the spies. He has a lot of knowledge and experience in the espionage field.
Horikita Suzune is also a great character. She is highly competitive and has a strong sense of justice. She constantly tries to rise above the challenges in the school, and her interactions with other characters are full of tension.
Kushida is one of the main characters. And there are other important characters like Ayanokoji, who is very intelligent and often has his own plans. Horikita is also a key figure, with her own ideas about how to succeed in the school's competitive system.
Horikita Suzune also plays a significant role. Her determination and growth as a character are likely to be explored further in volume 4. She is constantly striving to improve herself and her class's standing.