Quoting Blair Fraser, reply 3I never did say it was a new faction...but I didn't say it wasn't either.
Are the Vasari having a civil war? or a slave-world uprising?
and more importantly will the "new" faction ever be added in with one of the expansions?
End of Bootss1's quote
Hmm... If "Chaser" is another faction, then we get to play it. 
Yay!!
If "Chaser" is not a faction, then probably a AI player or Hmmm...., haha, silly idea, but what if the Vasari, accidentally opened a rip in the fabric of matter/energy/time? And what we have is an imploding Universe!! A physical phenomenon? Not baddies to shoot at with guns and lasers, but some energy wave that is decimating physical planets, ships, and people? Very very bad thingy. But maybe a really really good idea. What do the humans, advent and vasari do to survive something that it looks like they cannot survive? Haha, if this were a Larry Niven SF novel, we'd get some bang up blockbuster story, and a wow ending to cap it off.
But could this be done in a game? Make it playable and fun, or scary as the case may be? Ahhhh.... you know what... haha... if this were .... lets pretend here for a second, okie? Lets pretend this is Guild Wars made by IronClad. So what we have is a start, a beutiful, but fighting start place. We fight vasari, we fight tec, we fight advent. But then what happens? In GW of course the baddies bombed the heck out of the good guys. For our Pretend Sins/GW "Chaser" as a horrendous natural phenomenon (Avalanche or Tidal Wave) we have it catch up with us. Catch up with our universe. What happens? Look at GW. Its lays waste to everything. Way cool, smashed planets, half-torn Suns dangling skewed in space. 90% population gone! Only a handful of ships and humans, vasari, advent left. New coalitions, the pirates now join the tec against the vasari. The advent are a peripheral force. New graphics to make your eyeballs drop out.
Haha, and then what? We are still fighting the vasari, who now have no place to run, and with only 2 or 3 planets in system instead of 20-30 and weak resources, and perhaps a radiation sickness left over from the Tidal Wave? Meaning we all have to have double plus shields to simply stay alive. Large bodies, stars and planets having higher rates of decay or radiation damage. Like the wormholes can give damage or the blackholes in 7DS do now. Except apply if to everything. except the asteroids, and now there are a ton more, since most of everything was blown sky high, there are all these little "pockets" where the radiation is close to zero. So that is where people hang out. But the big planets and suns are where the resources are now. So we have to go to them to get resources. Haha, this is fun to think about, but perhaps one heck of a trick to pull off. But why? Why does it have to be hard to build skyboxes that look different? Or throw in a lot of asteroid in the mix, instead of so many planets? Or give the planets a background radiation level in the same way that wormholes and blackholes do now? It seems like a lot, but i am thinking it could be done.
Anyway, my mind ran off with me, but its a neat idea i think. At least it would be a shaker-upper just for the players to play in a new playground with different settings.
I wonder if this could be done as a mod?
-Teal
Sins Forums
Still secret... but we are trying to figure it out too. 
And i was hoping to get in one more game of Sins before i checked out. 
Stardock Forums
not sure how it would be easy, or even possible to stop them, given the Dark Fleet Veer was destroyed(or was it? the Vasari tech that makes free ships, forget what it's called, can't just pop out frigates and cruisers from nowhere...) by this unstoppable foe, how can the noob TEC or even the hateful Advent stop them?