So, after months grinding I managed to get to Rank 5 on Solaris United.
And that was it. Nothing happened, nothing changed. No cutscene showing the big ''Secret'', nothing. It was like ''Ok then bye''. I already knew the big reveal, so it wasn't a problem for me, but it may be a problem for people who do not know in the future. Might want to check it out.
Also, I don't know if the characters are supposed to change in any way, but it also didn't change so... Yeah, Nothing happened when I got to Rank 5 SU