Under the (very likely assumption) the tanuki is right about her being human, it should be all but confirmed now. No way the young girl we saw last time started pretending to be hinakos aunt before the series even started unless she is immortal. And the only reason a human would be interested in hinako before the series started is because hinako got shioris blood and that human shares a connection with shiori.Could Hinako's Aunt from Ooshima be the woman who gained immortality through Shiori? After all, it was never made clear whether the explosion actually managed to kill her.