From the latest GW2 email:
QuoteEarly in Guild Wars 2: Secrets of the Obscure™, you'll discover rifts—tears in the fabric of reality—across Tyria, through which strange, demonic forces are appearing. These are the Kryptis—they're mean, meaty, and it's up to you and some new allies to find a way to stop their incursions from the Mists.
Chief among your new allies will be members of the Astral Ward. After joining forces with them, you'll get access to the Heart of the Obscure and its associated Mastery line—essential components in your quest to hunt and close rifts.
With the help of the Heart of the Obscure, you'll find and open rifts across Tyria, revealing Kryptis invaders who had been hidden from sight. Defeat enough of them, and a more formidable champion will appear for you to face. Taking down the final Kryptis target will allow you to close the rift and grant you Kryptis Essences: powerful materials you can use to craft weapons, armor, legendary armor, and bait to lure out deadlier Kryptis from future rifts.
Didn't EQ2 do something similar with the void expansion?