[TCman]

I guess Unohana's letter to Isane is her will/testament. I suppose that's a pretty clear death flag for Unohana, right?

Spoiler for what the outcome would be between the death match between Unohana and Zaraki:

- Unohana dies because of her old wound; Zaraki was able to stab her at that old wound again when Zaraki finally progresses further in his fighting skill;
- or Unohana may survive but may loses an arm of something like that which means she can't fight at her full potential anymore ever, i.e. remain as head of 4th Division.