Hahahah, don't worry, Vita. I named my user after my most used character. He isn't able to drain someone's blood to kill them like that, that would be slightly overpowered xD
He can only siphon small amounts of blood around a person's injury, as in, blood that is close to the surface. The main source of blood he uses will be external pools of blood, either from his, or his opponent's flesh wounds. He won't be going around taking 8 pints of someone's blood then leaving them in a ditch, so you don't need to worry about that.