Guys, don't fret.
The SBS will just say, idk, "Issho was the guardian of the Kingdom X"; not more, not less.
I am hyped.
We will have a sneak peek of what the Admirals were doing before the TS. It will be nice since we have always wondered about It
It happened in the past and their plot will be expanded (for example with how and when Fuji blinded himself or Ryo's tatoo) when the time is right.