So trying to understand what you are saying. This game is in pre-alpha. There is no millions of people all up. I'm not sure on the back numbers or people interested overall. Even most groups aren't huge either. I'm apart of a pretty big duchy that all up hasn't broken 100 people. So looking around for a Russian group/clan that is 500 strong. Besides the why does it need to be that many? I'm not really up on EU server in general, to give you any sort of an answer of how many Russians there are.
There are a few different kingdoms on EU either way. I know they have some communities within them that don't speak English. Maybe one of them can reply if there is a group of Russians or not.
Not sure if you are asking for your own Russian server, since without the numbers, that won't happen anyway.
Which either way this game won't be massive. Which is fine, it's a niche game that not everyone will be into. Be better to join some of the EU discords channels, talk to them to see if you like them, there are other Russians around.