jaspr
OMG!!! I just had a mind blowing idea author-san!!! What is in future he finds a way to store hearts IN THE PUPPETS!!! That way he the puppets could possibly use jutsu like his masks in future and he would have as many spare hearts as he wants on standby. (eg. each puppet has a detachable mask that holds a heart which can quickly and easily transfer itself into Kakazu's body).