I don't think the Fallen took part in the collapse. Here's part of a Grimoire card: [quote]The Fallen "We have butchers at our gates - four-armed and eager for slaughter." 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.[/quote] Here it says "in the wake of the Collapse." They weren't a part of the collapse. The Fallen are often depicted as scavengers. I view them as the smaller fish that follow sharks and eat whatever scraps the shark leaves in its wake. The Fallen probably follow the Darkness and loot the ruined worlds that the Darkness destroyed. It's likely that the Fallen were a people that fell victim to the Darkness, and now have been reduced to nomadic scavengers that try to take advantage of the doom of others for their own benefit or survival.