In the light novel, Ayanokoji is clearly the more intelligent one. He has a unique ability to analyze situations and people's motives deeply. Ryuen often falls into Ayanokoji's traps because he doesn't fully understand Ayanokoji's true nature. Ayanokoji can anticipate Ryuen's moves and counter them effectively, while Ryuen struggles to keep up with Ayanokoji's complex thinking.
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.
You could start by using technical jargon and futuristic terms. For example, mention concepts like artificial intelligence, virtual reality, or quantum computing.
When Ayanokoji says 'I'll use any means necessary to achieve my goal', it reveals his somewhat ruthless side. He is not bound by conventional moralities when it comes to reaching his objectives. In the light novel, this could be a result of the cut - throat environment he is in. However, it also makes him a complex character as readers are left to question whether his actions are justifiable or not.
One of the notable quotes by Ayanokoji from the light novel could be 'I don't care about victory or defeat. What I want is absolute control.' This shows his unique mindset that is not focused on the typical goals of winning or losing but rather on having power and control over situations.