From Bungie: "House of Wolves will have a new cooperative end game activity focused on variety, replayability, and skill – a new battle Arena called The Prison of Elders." [b]Variety[/b] - I imagine there will be weekly variations, similar to the nightfall. These variations will not be limited to simple burn modifiers. I believe there will also be unique effects that produce challenging encounters. Bosses may have several different stages--perhaps these A.I.'s will change form/tactics over time. In other words, the bosses may not simply be bullet sponges. [b]Replayability[/b] - The rewards must be broad and challenging to obtain. These treasures should have quite the incentive to acquire. They may have unique perks/attributes not found anywhere else in the game. [b]Skill[/b] - I believe there will be different tiers of The Arena. There will be easy to hard to insanely difficult variations. There are supposed to be "hundreds" of weapons going to be released. Some weapons will require high skill to obtain; some, not so much. I believe that The Arena is the PVE counterpart to the Trials of Osiris, which is a PVP mode. They are both 3-player team modes. If this is the case, expect the following: From what has been data-mined(perhaps now out-dated according to DeeJ), Trials of Osiris offers legendary weapons akin to already existing exotic weapons. For example, the legendary handcannon from Trials of Osiris, The Jewel of Osiris, is very reminiscent to Hawkmoon. [b]The Trials of Osiris weapons have unique perks tailored for [i]PVP[/i]. Thus, we can expect The Arena to have Legendary weapons that also have unique perk combinations, tailored to [i]PVE[/i]. [/b] [b][i]Please note:[/i][/b] I am [i]speculating[/i] about what is to come--this information is not confirmed. We will know a lot more tomorrow, perhaps. Why? With the update before The Dark Below, the patch contained a huge amount of data pertaining to that expansion(it was a 2 GB install). Expect the same size of update tomorrow(1.5-3.0 GB). The information from this install will be data-mined for accurate information pertaining to the next expansion. What do you think The Prison of Elders(I.e. The Arena) will be like? Let me know in the comments below.