Under the basis that Ryuma lived in the same era as the WG which didn’t exist until post Void Century which was when Wano sank and that Ryuma is buried in modern Wano not the sunken Wano which means he lived and died in modern wano
It was always said " Outside threat " or some other phrasing not World government spcifically.
Ryuma lived during the time it was called " City ot country of Gold ".
Which is old wano. NEW wano , never such advancement as Borders were built up.
Post automatically merged:
Because if he was his corpse wouldve been at the bottom of the sea and not thriller bark two years ago.
Mt fuji of wano existed back then too and so did Ryuma.