Here's the previous topics. Lucon can give a less detailed response, but if you want to know a lot about it, here;
These are the ones that Lucon listed in the Midnight Flower Topic in Events at the bottom of the Forum. That's also where the RP will take place.
Also, in Lucon's words (I'm too lazy to come up with my own XD) The Midnight Flower is "Helena's orgonization for all the misfits, and outcast" and it's also about "Maria's evolution to hollow/arrancar, the beings she has hunted for ages". This may consist of Soul Society outcasts, lone Arrancars, Vaizards that have been found out, Quincies, special humans, pretty much anybody who's been betrayed or is an outcast. Anyone who works directly for the Espada, the Soul Society, or certain other things would normally be against it. Also, simply because you work for the Soul Society or something like it, doesn't mean you have to be against it, and some outcasts could be against it. It all depends on your character. Wow, I got side-tracked. Anyway, quoting Lucon again, "We are an organization that offers a home for those who have been betrayed and abandoned. Rouge shinigami, vaizards, arrancar, and spiritually aware humans, are all accepted into the ranks of the organization." Hope this helped explain.