Across the Abyss

While you were crawling around the swamp, killing Imperial scums, the Resistance warriors have searched the entire Irdrich. And you know what? Nothing! No Lictors, no center of illusion, no new rifts! Evidently, a couple of holes in the fabric of the illusory world won't make it collapse. What a pity!
The only place we haven't looked at is that mountain in the north. Aviaks are terrified of it, and you can't get there on foot - there is a massive gorge between the Windy Hills and the southern island. This is hardly accidental. Tep doesn't want to let us go there, which means we have to find a way at any cost!
Find a way to get across the abyss. If you find any rifts in the illusion on the other side, use it to summon Charles de Doucer. He'll get the rest of there in a jiffy - don't you worry about that!

There are more rifts in the illusion with each passing day... But it doesn't seem to weaken the enemy whatsoever.

Have you found the key to the last puzzle? That's great! I will signal the Resistance to start searching the Crystal Mountain.