Zundar is the commander of the Conquest Club's operations. As such, Akoya follows its orders.
Akoya and Arima are on good terms with each other. They get along well, with Akoya being seemingly fond of Arima to an extent, as the latter is always shown making straight-forward remarks when Akoya either boasts or praises himself, as seen in the manga. Not only this, but it's shown in the Otome game that Akoya's fondness for Ibushi exceeds platonic adoration, heavily hinting that he may have a crush on him.
Ryuu is in the same class as Akoya. Although not much interaction has been shown between the two in the anime, Akoya does not seem fond of Ryuu's behaviour. He is often shown making comments on how Ryuu might be interested in him, much to the latter's dismay.
Akoya is shown to have some form of respect for Io, and possibly a crush. He first interacts with Io in episode 6 when he asks him to join the Student Council as a treasurer because of the latter's extensive knowledge in finance and the stock market. Akoya notes that Io was the most suitable candidate as a forth member of the student council, because he had the "elegance" and the "reputation" suited for his association with the said council.