How many Black Knights (Black Wings Generals) are there really?

actually I wonder the canon of that image. lilin and neinheart are strongly suggested to have no actual communication with each other since he left, and no one on Rien seems to know anything about Ereve. Also, while I do believe the alliance thing, I find it hard to believe that all of the resistance went to Ereve despite their hate of the knights.

The resistance hate the knights?
...actually, I can see that. The Cygnus Knights didn't do anything when the Black Wings invaded.