Im just gonna be honset here: ya know how luffy wears a straw hat and so did the user of the human human fruit before luffy? Well i think the reason everyone referres to them as the drums of liberation is 1: Nika carried a actual drum around and would play it so prisoners and armies alike would know his presence was now there or 2: The reason nikas fruit users hearts beat is because in the end someone must have removed nikas heart in some way and proclaimed that his heart was the real drum.
