Hm... well, my character (who will remain unnamed for now) will be a member who was born into the group, with his father probably being one of the older members. As he grew up he was used for blood rituals, and was taught of course that what they were doing was only to unlock their lil utopia. I can see him being a bitter child, maybe even rebellious against their God, but always coming back. I kinda want him to have ties into the Otherworld, maybe he can use in mildly as a weapon? Or maybe see the future? Regardless I would want him to have some kind of tie in with his father's death as well. Maybe his father was a sacarifice, and it was he who had to kill him? Now I imagine him being held highly and with respect in the inner most of the sect. He would be downright evil and demented, though would come off like a gentlemen to anyone he met.
I don't know, really that's just one of my ideas.