Yes
No
Maybe
- They can't draw blood or take it from a wound. They can only use blood that is spilled.
Do you know how hard it is to get enough blood to spill from a cut on the wrist in order for the character to create a viable weapon (and we have to remember here the character can't draw the blood out either). If they cut a more vital place, say the throat or femoral artery in the leg places that bleed profusely and in large amounts, they'd bleed out to quickly . . . not to mention how do they stop the bleeding, does the character have some kind of healing factor too.
Also how much blood is needed to make a weapon. Are we talking equal value?
Currently, I still see some serious holes that need patching. I'm only nit picking because this is going to be an advance game and I want people to have advance quality abilities . . . so I'm going to be asking everyone to hash out their abilities.