: How do you rationalize this with the story as we know it?
It is the story as we know it. Your guys port in, there's a large Dark force already on-site, their units react to your presence by a) directly defending against you and b) cutting off your retreat by destroying the Knot once you're too far away to protect it. A few weeks later, the Dark figures out how to use the Knots and the Head alerts the Light to this fact.
Story-wise, it's obviously simpler to assume the Wights are just part of the on-site force that aren't actually on the map. After all, it's not like the few dozen enemies in Homecoming and Flight from Covenant can actually be the full extend of the Watcher's "earthshaking army." :-) The story clearly indicates that there's lots more Dark units around there.
Again, story-wise, if the Wights teleport in via World Knot, you have to explain why
a) there wasn't a visible Knot effect,
b) no one noticed the use of the Knot and commented on it in the narrations, or made the Head's warning superfluous,
c) the Wights had to wait until you were so far away before teleporting in (What would they care if you killed them as soon as they appear? They'd already be in range)
d) the Wights took the trouble to leave the Knot and go outside it before detonating, and
e) the Dark didn't send a more substantial force to catch you from behind.
I'm not pretending that all of these are major objections, but it certainly seems unnecessary to believe that the Wights were teleported in.
--SiliconDream
