So what exactly is the story here?

What is the great secret of the Storm Wardens?

Were they invented by FFG?

To answer all your questions.......

Yes.

At least the last

We don't know for sure what happened. If you want to have a digest of the story we know for sure, you have this page . The thing is, there is next to no clue to what exactly made the Wardens to bear a secret they don't even know of themselves. It's a bit Dark Angel-ish, but with even fewer people who know

Uhhhhhhhhh... Check "The Nemesis Incident" supplement on the DW support page. It explains the deep dark secret of the Storm Wardens.