>>49125450Invaders = established/known entities who had a mutual interest in coming aboard. basically, these girls don't need the training wheels and have established fanbases and connections to phase girls.
Gens = hand-picked by fishman and scrutinized/auditioned more closely to try to find diamonds in the rough, they didn't just get waved in past the line like invaders.
Not like being an introduced gen is bad or means you were worse than someone who was already-known just coasting in, I mean if they only took lower-risk girls in Phase wouldn't be what it is at all. Just i's a different criteria set in the beginning. Or at least, this is my headcanon of the distinctions.