As far as I know:
we only see them in one brief flashback.
Did they play any significant role off camera, or in a deleted scene perhaps?
Are they even still alive?
At the end of the film, Supreme Leader Snoke instructs General Hux to find and return Kylo Ren so that Kylo
Earlier in the film, Snoke calls Kylo the
If Kylo still needs training and he is in command of the Knights of Ren, it is logical to conclude that the rest of them are also in training during the film's events.
Nobody knows. Expect this to be answered in one of the many future Star Wars-movies.
It does seem the organisation does not exist anymore at the time of TFA: