Perhaps this will help.
There are (or were) lots of players who claimed to be bad asses, and members of bad ass guilds with spooky names. They never did anything "bad" in game... Just trained.. "Yar, were tough guys ... and we'll take over Yliakum or something.."
Avoid this at all costs. Focus on doing what bad guys do, and do your best to make others think you are good. Once its discovered that you're a baddie, you really lose the ability to play the wolf in sheep's clothing.
Do the quests that lead to temple access, and pay close attention to how those npcs operate, who they work with, who they know or vice versa etc.. Do they go around screaming that they are cultists?
No, with one exception, they do the opposite. They enlist others (like yourself) to do their dirty work for them.
Try to get some other players to join also. You really need to have a group of black flamers unless you like playing by yourself.
Keep all bf stuff between yourselves, and wreak havok as covertly as possible.
Be prepared to toss your character if you are discovered and reported to the authorities. Its just part of the territory.
Have a front of some sort. Be someone in society. Be a baker and get a job at the Stonehead, or be the town Xiosia worshiper who hands out flowers and smiles at everyone.
In hindsight, its probably better for players to be unaware that you are a bf member. That's right, don't even let them know oocly. People will subconsciously treat you differently - unintentionally of course. Likewise, not letting anyone know about it oocly may make it that much more mysterious.
That's my two cents at least...
If you want some examples, look at the ingame roleplaying events section and check out the following threads:
Auctioning Victims
The Guilt of Jacula ( and sequels )
Nightmare Dust ( think that's what it was called )
There was another by Tadano Hitoshi.. I forgot the name of it.. It overlapped with "Poor Sick Dwarf" and some other events at the time.
At the time, we trusted the RP community enough to post the logs to these roleplays. Most of the players involved did the right think and isolated this ooc info from their characters. We had a blast doing this and wanted to be able to share it with everyone else.
Good luck, and whisper bless
Oh PS, there used to be more BF activity than what you see posted in the in-game rp events section.