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.
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.
His character could become more mature. Facing the situation of the pregnancy, he would have to grow up quickly. He might learn to be more empathetic towards the girl's situation, understanding the physical and emotional challenges she is going through. Also, he could become more decisive as he has to make choices regarding their future and the future of the child. For example, he would need to decide whether they should keep the baby or not, and how they would support it if they do. All these experiences would shape his character in the fanfiction.
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.
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.