"The Fallen are ruthless scavengers. Brutal and uncaring, they arrived on their massive Ketches in the wake of the Collapse to loot and pillage our devastated worlds. There are hints of ancient nobility to the Fallen - the scars of lost grandeur. The Kells of their scattered Houses still claim to be royalty. But they leave only grief and wreckage in their wake." (Information from bungie.net)
The trailer shows a group of dead Awoken, and not just any Awoken, but the Queen's Gaurd, and we see images of Fallen in some kind of snowy area. Now, we know that the Queen defeated the Fallen, and took them in as guards or pets, but now they have obviously rebeled against her, killing her elite guard and apparently after something, but to what end is not made clear.
The question remains though; why did the Fallen rebel? Where exactly are they going, and what is their true purpose? Bungie, the developers of Destiny, is pretty good at hiding information and leaving enough out in dialogue and the grimoire cards to allow the players to think about what is actually happening in the Destiny universe, without too many specific details.
So what do I think is going on? Well according to the background information of the Fallen, they used to have nobility, and most likely a leader or some kind of role model that they used to follow. Now, there has been mentions of the “Prison of Elders” earlier in the game, and has been confirmed to be in the House of Wolves DLC. My guess is that there are Fallen, specifically the House of Wolves Kell or maybe the Archon Priest in this Prison of Elders, and the Queen's Fallen are out to regain their lost leaders.
So my theory is this; I think the Fallen allowed themselves to be defeated by the Awoken, and willingly worked with them to get closer to the Prison of Elders in order to become something more than scavengers, or perhaps re-obtain their lost glory. Of course, anything could still happen, but I do believe that it is a good way of combining the background information of the Fallen and the events that occurred in the trailer itself.
We will find out one way or another on May 19 which is the release date of the DLC. Think that you have another idea of what is actually going on? Want to hear more on Destiny? Tag us on twitter (@geekswithbeards) and we can discuss it!