My roommate has been seeing me play earth empires and wants to create a country. is this going to be a problem coming from through same router and isp?

Contact the game mods. There's a safelisting process you can go through where they'll allow two people to play from the same IP.

There are a lot of rules about it though, for instance, your country and your roommate's country can never interact with each other in any way, whether it's landgrabs, FA, allying with each other, etc.

I don't know all the rules as I don't have any need to be on the safelist, but like I said, if you contact the game mods for whatever games you and your roommate intend to play (FFA, Alliance, etc.) then they'll be able to give you more information.

contact martian to get instructions, at least he will direct you to right mod depending which server(s) you 2 will be playing.

ya, there's a safelist for this