Great chapter. Even when one thinks he is finally on the back foot, Riboku completely turns the tide once more.
I do not think Dansa is dead (yet anyway). Bananji’s presence took all of the Qin side completely by surprise.
Considering how quickly Bananji moved in tandem with Futei, I believe that Bananji bypassed the Dansa Army by sending the Gakuei Army remnants (and possibly the Bananji Army infantry to allow Bananji’s strike force to travel at max speed) to pin down the Dansa Army long enough for the Bananji Army to get past.
My guesses as to how Ousen gets out of this mess;
1) Ousen himself either has some high level tactic up his speed and/or he actually physically packs a punch. He would pull the former on Bananji (who is an infamous dualist) and/or pulls the latter on Futei who is leading a significantly smaller force and is nowhere near as powerful as Bananji.
2) Someone strikes Bananji from the rear. I predict either the Gyoko Hou and/or the pursuing Dansa Army. Even if no one is capable of defeating Bananji in a dual, no one needs to if they destroy his army.