Flaming Ninja Starknives

A traditional Japanese Prince has a dark secret. He has unwillingly inherited the family Daemon, called Akuma. It has been in the Yamoto clan since the Sixth century. As their leader, this beast is his responsibility. He would like to be rid of this monster, because he is not only troublesome, when he takes up the family sword, the beast enters into him and transforms the Prince into a fourteen foot tall monster who enjoys nothing more than devouring men's souls. This beast will also throw flaming knives of fire that can destroy anything, even modern Kevlar, after which it burns the bodies and souls of those who encounter them., And THEN it drinks their essence
Which is one thing - the real problem is that everywhere the Prince goes, Akuma is chatting away, wanting him to do mischief. One one hand, not such a burden, for only those initiated into the ancient rite can see this Daemon - That is until the Prince takes the sword, then everyone can see it. But then they tend to die, Akuma drinks their soul, and so the not-so-little secret is kept.
Then, of course, the pretty girl turns up, and if the Prince thought a fourteen foot tall monster that wants to drink your Soul was a problem, well that was just the start of things ...