The grand finale of the series as it was shown on TV, but there are still two unaired episodes left. The whole "nothingness" shtick is clearly a reference to the common martial arts idea of using your opponent's strength against them, but it was exploited so literally that I simply couldn't find any less half-baked way to translate it. The flashback in general doesn't make a terrible lot of sense as Goro lost his parents when he was even younger, but maybe it would have been explained later, had the show not gotten abruptly cancelled.