[@Cleverbird]Couple things, after Gold and I put our heads together:

After reading your description of blood magic, we were hesiant because we felt it didn't jive with how we envisioned the seting. Hard to put consisely, but here goes - Blood magic is kosher in the setting, but in a more suble way. We'd prefer to see the effects move away from buff/debuff terminology and direct manipulation. Its effects and the procedure of casting should be more nuanced... ritualistic? Grounded more in ceremony and something resembling voodoo, opposed to waving one's hands behind the frontlines and churning the lifeblood out of your enemy. 

Do you remember the witch, Mortianna, in [i]Robin Hood: Prince of Thieves[/i]? There's a scene where she uses blood, saliva and other substances mixed together to discern visions of the future. This is the sort of magic we have in mind. Subtle, with often unforseen effects, but also powerful in the right situation (as evidenced in the Conan stories where sorcerers might extend their lives, call forth extraplanar creatures, conjure illusory effects, and so forth).

Also, on the matter of gods - this blood cult is free to believe it sources its power from whatever deity it worships. But as to whether that deity is real or not, there is no solid confrmation, nor denial. It should be a faith-based matter. How a sorcerer choses to interpret his dreams is on him, for example. There [i]are[/i] powerful beings and monsters out there thay may seem godlike, and folks can choose them as patrons, but all 'godhood' is on faith.

Other than that, there aren't any glaring issues. What are your thoughts?