Don't even get me started...
My Great War universe —cringeworthy name not withstanding— is grandiosely-scaled; a bit like Warhammer 40k.
For the sake of exploiting the vast militaries contained within it'd be an RTS/TBS — think of the Total War series but wherein the campaign map takes up a quarter of a galaxy.
Specific characters are vastly irrelevent and always have been in this sort of game, although they do exist;
But specific nations, that's another thing. Obviously here comes the rock-paper-scissors trumping, though I would rather make gameplay not so simple.
Anyway:
West Fletcha — Best defensively, cheapest units.
East Fletcha — All-round but are not actually good at being all-round.
Nidara — Very speed-capable troops but their morale can't be expected to hold out long in a prolonged fight.
Oralia — Small nation but with high quality soldiers. Mostly uses W Fletchan tech.
Edo — Even smaller than Oralia, and with average soldiers. In game terms it'd exist really just to be a political influence, and provide a challenge to experienced players.
Kendoo — Best space units, good ground units.
Silvara — Good units, but most of their 'battles' will be political.
Maroké — Best all-round, space units are second to Kendoo.
Ehyula — Really just an underling to Maroké that must answer to her every call, actually completely sucks all-round apart from having the only ground soldiers that can fly by natural means.
In any respect it will be an unbalanced game, but that's the thing, some galactic empires are better than others.
Canonically though most of them are allied and the same race, but now I feel like I'm just going on and on and on so I'll stop.