Sith'ari Darth Bane

Another hint: He died at malachor V at the hands of the exile. Shades of past sith lord, Sion.

I believe Andeddu will treat Bane like all others and pretend to indulge him, give him a technique to prolong his life even after being struck down. Allowing him to live albeit in agony until he gives up because his powers are diminishing or just plain can't best his opponent. As we saw in rule of two, he was very good at dueling, but not the most refined nor immune to being struck.

So I believe Bane will die either fighting to the last, or in a graceful dignified fashion acknowledging his apprentice one last time.

Mind you this is speculative and merely my prediction.

Could instead be a rematch of that-betrayal accusation in the desert, after bane disposed of the assassins and Hetton. Except this time Zannah will have more tricks. If back then she held off his full fury, I wonder what she can do now 20 years later.