Alright, here's what we've got so far:
Lots of people confused about the end of TFL and the later TFL events described in TFL. To clear things up:
The Deceiver dissappeared after the battle at Seven Gates. Half a year or so later, around the incident at Forest Heart, The Nine discovered that the Head had been double-crossing them, and thousands of people unexpectedly spung up to defend him - two of the Nine died in the ensuing civil war. While the Legion headed up through the Dire Marsh, the Deceiver crossed the Cloudspine at the Stair of Grief. As Alric went to kill Balor, Madrigal fell. Somewhere in there, or just after, the Deceiver was plunged into the raging Dramus river (Tharsis was still erupting, apparenly), and the Head vanished into history.
Now, my logical conclusion from all this is that, the Deceiver dissappeared through odd angles to gather a new army. The civil war started, the Deceiver crossed at the Stair of Grief and proceeded to crush war-weakened Madrigal. But Alric returned and gathered an army out of the survivors in the North (around Tandem), and pushed the Deceiver back into the Stair of Grief, plunging him into the Dramus.
The big question here is, where did the Head go?
I don't particularly like Ducky's theory because, like the Watcher's arm conspiracy, it relies on the weak evidence of graphical mistakes. But it's a theory nonetheless, so keep advocating it - and others, please, keep fighting it! Please! ;-)