i think the 6 disaster raids are the ones that sealed diabolos away in her realm
after in those tidbits of info that we get from loading its says that she was sealed away by disastre now we know its spelled disaster so there you have it
thats the story behind them
another hint is those raids only became accesable after you finish realm number 1 where you get both diabolos and amon
so yeah thats my take on the story behind them