I understand that the brothers are fighting, but the third is such an idiot. The second is fair in how he retaliated his brothers attempts to weaken his troops, not to mention they're flanking and would take less damage anyway. Did he think he'd just sit there and take it?
Peak manga, doesn't try to drag out shit and the end battle correlates to most of the events shown before. Beginning is very meh, but seeing touma vs setsu it is the best experience known to man.