[@Sigma]
Well, my ideas are:
1.) Alien invaders with strange mindset though certainly not bland across the board.
2.) Interstellar Corporate participating in this war for mining rights and future profit.
3.) Grim, gritty human aliens from a death world planet whose sour experiences paint their outlook on life among others.
4.) Space Hungary just because

There are perhaps more but these are the most preferred choices to me right now.

As for writing NS, I can help you come up with one which is simple yet has sufficient detail for other players to form a basic impression on your faction and its abilities.