I've seen speculation on the "Dark Founding" in the past, but nothing terribly concrete. So what do we know about it aside from the fact that it is, in fact a different entity from the "Cursed Founding".

Do we know what caused it? What chapters were created during it? or what exactly marks it as "Dark"?

I've always considered it a catch all for people who want to make their chapter special, but I'm just curious if there are any catches to that bit of fluff.