Please Expllo, do speak up about your concerns. I believe that the ability is quite balanced if handled properly. I also see the concern within such an ability, especially due to the fact that it does not seem to have a disadvantage in it's offense, but like me and Green have stated, it completely lacks defense. Not only is the chance high that a strong enemy can pull out Jacholaus, the Meister is completely open to attacks. He would take the beating nevertheless. The enemy can get a win:win out of this by simply suiciding against the Meister, should he not be able to withstand Jacholaus attack.
Not only that, but as Venom already said, a person who is completely bloodlusting can hardly resonate with a "normal" minded being. If the Meister cannot fully resonate with Jacholaus, the drain would stop or even backfire.