In the mess-room scene where Six and One are talking about The General, the whiskey bottle in front of Six moves from his left to his right from one cut to the next, without Six touching the bottle.
4 is accused of murdering his father, the emperor of a principality. However a principality is ruled by a prince. An emperor rules over an empire.
Five refers to Hiro as Four's stepbrother; because they share the same father but have different mothers, they are half-brothers.
When Four comes into the room to defend Akita and take the blame for outcome of the battle, Four's Royal Emblem on his chest is upside down compared to everyone else including his Father's.