The Return of the Genasi
Since the beginning of recorded history, the elemental Genasi had been keepers of knowledge. They maintained the shrines, libraries and academies of Ioun, the god of knowledge, skill, and prophecy.
Then, suddenly, they vanished 50 years ago.
Now, with just as little explanation, they have started to rise up from the earth, but with none of their prior knowledge or expertise. In fact, most have no memory at all, being little more than functioning automatons. Most of the time, one of the recently risen Genasi will wander naked into a town asking random questions until someone is nice enough to take them inside and clothe them. Not knowing what else to do with the poor souls, people will put them to work doing simple manual labor.
What has caused these masters of knowledge to disappear? Will they ever rise back to their former glory?