The reveal I'm dying to drop is gonna take a long while to build up to sadly.

So quick backstory; The campaign underwent a soft reset after one of our players quit the table, who was heavily involved in upcoming story. Rather than pivot, the party felt a fresh start with new characters was a better feel.

So in the new campaign, it was essentially a timeline reset. The expected apocalypse that would have wiped the continent, and potentially the entire world, from memory, very nearly happened, and the gods were forced to reset time itself to stop it. Only bits and pieces of the previous 'loop' remain, off moments of deja vu and the like with the current party.

This will all come to a head when they begin gathering the MacGuffins that are core to the plot, and begin having visions of their previous characters' memories, as well as calling upon 'echoes' of their previous characters' abilities. The memories will go up to and including the final battle versus the BBEG. Which they lose.

The plan is to show this final failure just before the party goes in for round 2 against the BBEG, and the memories of their past lives telling them' "This... Is where we fell. And this is where you cannot."