As spotted by Tails' Channel on social media (thanks, VGC), the website displays modern Sonic, classic Sonic, Shadow, and a fourth slot that's currently blank with the words 'coming soon' displayed underneath. You'll need to click the blue star icon on the right-hand side if you want to swap between Sonic and Shadow.
As for who this mystery character may be, we honestly don't have the foggiest idea at the moment. It could well be a 'classic' version of Shadow with shorter limbs and a more 'cutesy' vibe, but it's probably more likely to be a completely different variant of the anti-hero.
Either way, we'll find out for sure either on or before the game's launch on 25th October 2024. As a reminder, Sonic x Shadow Generations contains a full remaster of the original Sonic Generations, with additional content included starring Shadow himself.
We recently went hands-on with the game and came away feeling pretty optimistic, albeit with some slight concern regarding the game's potential performance on Switch. Check out our full thoughts below.