[quote=@Mikellh Dejax]
I see. How should first contact go about? And should the SF be the ones who actually fire first?
[/quote]I think it's more fun if it's left ambiguous.
From general SF point of view you'd be violent invaders who suddenly appeared at our borders and kept murdering humans unprovoked.
From your point of view you made first contact with one of the Starfleet's ships prior which either offended you deeply and/or stole something precious to you.
As such you're out to get back at those people and also to recover whatever was stolen. The rest of the humans are merely in just your way.
How does it sound?