The Demon Knights are a group that started out in the transformer Fanbase on the internet. Unwittingly they helped lay the seeds for the "counter culture" with in that fanbase. The Counter culture being those that wish to just have fun with others of the same interests and not feel as restricted as they are at the "big sites", though not just mere spammers, they are a tight knit group that really pulls together when need is there, but otherwise feel free enough to be themselves and not conform to any "standard" of what a poster should be. They have their own website, and seem to be welcomed for their quasi-celebery on the smaller sites in the fandom.
I am one of the Demon Knights.
UPDATE: Although the group is still together (with a few exceptions), the name "Demon Knights" is no longer applicable to them. Not too long ago, the website name was changed to "The Transformers Realm" in an attempt to distance themselves from a former member and his misguided actions.
The Demon Knights, per se, no longer exist.