[quote=ASTA]
What low tier nations?
[/quote]

Quite simply put, a nation which has lower technological prowess, military strength and/or economic power when compared to the other nations, or nations which would be relatively easy to defeat compared to the other nations in the galaxy

Given there's a fair amount of anti-matter floating around, the Valkian military could be considered this as they don't use shielding, meaning anti-matter bombs and anti-matter beams would be very, very threatening to them and until such a time they integrate shields into their ships, they would have difficulty stopping such an aggressor (Though even with shielding stopping anti-matter weapons is not an easy task for any one, I would assume)