I like it, too. It would be useful to have when running around dungeons and mysterious ruins. Just hope you don't run into a pack of undead. I think that a character may be well-advised to not charge it until the first creature killed outside of town, to avoid getting suspicious glances from the constabulary.
Which brings me to a question: Does the Blood Cloak always have the same amount of blood dripping from it? Or would it gradually lose liquid as the charge is used up? For instance, if you've almost run out of stored blood, might you only appear as some sort of crazed murderer with a few splatters?
Bonus points for providing a cursed equivalent.