To be honest Ryobi, what would be the difference. Or do you mean is it a ghost as we assume it to be or is it a creature of the non-corporeal world that never was a person? As for bringing itself to the corporeal world oni, you mean making itself corporeal again? Like a solid ghost? As far as I understand it takes a lot of energy for a ghost just to be seen or heard so manifesting itself as a solid being could be possibe but I doubt indefinitely.