I'm glad people love Kostya so much. He's one of my favorites to write and I love what he represents for the story. Sadly, I want to keep the scope of this project within reasonable means, so I'm not adding more routes.
I did at one point consider like a sequel-esque project but that would likely follow Selwyn's friend group, so it probably wouldn't have Kostya in there heh.
But if you are a Kostya fan, you might get a lot more than you expected out of him soon.