After the assassination of Serizawa Kamo, this left Kondou and Tonouchi as the remaining faction leaders. From what I understand, Tonouchi knew or even helped Kondou get rid of Serizawa but, then, Kondou killed Tonouchi at Yojou bridge to become the sole Shinsengumi leader. Was this an assassination or was it some sort of duel that was agreed upon?
Either way, what did Tonouchi expect would happen after Serizawa's faction was wiped out?
Was Matsudaira Katamori involved, at all, in this? Did he expect Kondou to kill Tonouchi?