The development can also be based on personal growth. Horikita is often very focused on her own goals and can be a bit cold. Ayanokoji could be the one to help her see the importance of relationships. Maybe he shows her how a more empathetic approach can help in achieving their class's success. This would lead to Horikita opening up to him more, and Ayanokoji in turn would start to show more of his true self to her. Over time, a deeper relationship could form as they both grow as individuals within the context of the fanfic.
Another theme is the exploration of intelligence. In the Classroom of the Elite Ayanokoji light novel, intelligence is not just about academic knowledge. It also includes strategic thinking, understanding of human nature, and the ability to manipulate situations to one's advantage. Ayanokoji, in particular, is a character who showcases a high level of intelligence in all these aspects.
One plot idea could be that Ayanokoji and Horikita are paired up for a special project in the school. As they work together, Horikita starts to notice the hidden depths of Ayanokoji's character that she hadn't seen before. This makes her view him in a new light and their relationship begins to develop.
They could be in a situation where they have to work together on a project for the school. Karuizawa Kei is initially hesitant because she doesn't trust Ayanokoji. However, as they face difficulties during the project, Ayanokoji's calm and intelligent approach starts to win her over. Their relationship then blossoms from there. For example, they might have to deal with a tight deadline and scarce resources, which forces them to rely on each other's strengths. This shared experience can be the foundation for their growing relationship.