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.
I don't know for sure. The ending of such a manga can be quite unpredictable and might not have been revealed yet. You could try discussing it with other fans to get their speculations.
The order of publication of Keigo Higashino's series of novels with Yukawa Manabu as the protagonist is as follows:
" The Sacrifice of Suspect X "
2. White Night Journey
3 After School
4 Malice
5 Secrets
"The Sacrifice of Suspect X 2"
After School 2
Malice 2
White Night 2
Secret 2
Suspect X's Sacrifice 3
After School 3
Malice 3
White Night Journey 3
Secret 3
The above is the main order of publication of the series of novels by Keigo Higashino with Yukawa Manabu as the protagonist.
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 great plotline is his relationship with his classmates. Some are suspicious of him, while others try to befriend him. His interactions with them gradually unfold his character, as he has to balance between being part of the group and maintaining his own secrets.
In the anime, Ayanokoji's appearance might be more vividly presented with colors and animations. However, in the light novel, more detailed inner thoughts and descriptions can be found. For example, in the light novel, we might get a deeper understanding of his complex psychological state when he makes certain decisions, while in the anime, it might be shown more through expressions and voice acting.