The Fractals of the Mists is made up of nine mini-dungeons, each with its own story and environment. A party of five will enter the dungeon and be faced with a random set of three of these dungeons at a time. Upon completing those three, the party will be transported to a hub to rest, repair, and merch -- and the difficulty scale for the dungeon will be raised. Every time the difficulty scale is at an even number, players will face a special boss encounter.
1) In content updates, we'll see more dungeons added to this.
2) Dungeons might be related to old lore and old GW missions. For example, Underworld and Fissure of Woe are in the Mists.
3) Possibly tied in with the up coming pre-cursor changes. I.E if you get to a certain level of difficulty / collect enough tokens you get awarded a pre-cursor / pre-cursor token. Likewise, possibly drops from the 'special bosses'.
Edited by Zedabi, 12 November 2012 - 04:21 PM.