They get changed as frequently as and when we have time to change them, provided there is are artists ready to provide a suitable versions…
Edit: I have a new Kairin, but have not had time to think about putting her up on the "main" site. Given we're not exactly maintaining the site right now, I may never get around to it. So, for the time being, you can enjoy the picture here.
It was created by
takumy.