[If he didn't literally have to breathe rhythmically for Hamon, he'd have held it. As it is, he furrows what Could be brows in his case as he thinks.]

A rather good question...I have no doubts there would be limits. It absolutely Cannot heal vampires after all. But I know not enough about the details of the art to otherwise answer...my master died quite tragically before he had even truly finished my training, and I myself perished not long after...I...

...I do apologize, but it very much is not something I care to experiment with either. The risks are simply too great.