I would like to dedicate my soul to Satan. Do I write the whole thing in my blood and sign it in my blood? Or do I write it in pen and sign it in my blood?
Sign in blood, as best you can. You might only get part of it in blood, if you can't get enough blood or you don't have the equipment to dispense the blood. Or, you might only get a smudge of blood. That being the case, sign in ink (preferably red).
