: The Callieach would want to go back to the other side
: because they were being slaughtered by the Trow! They
: decided to oppose the Trow, like all the others before
: them, and so were being killed. Before they were all
: destroyed, they used their magic to teleport
: themselves to the other side through a great hole.
: Many Trow were taken with them, probably killed once
: on the other side.
Yes, but if the Callieach were created in the known world, they wouldn't know about the Dark side of the world (short of very powerful divination), and, even if they did know about it, if they had been created in the known world to start with, the Dark side would have been no safer than the known world, filled, as it would have been, with assorted nasties.
: Spiders, Fetch, etcetera: all from other realms, as the
: game depicts.
We know the Fetch are from another realm. We don't know whether or not that realm is the dark side of the world. That is why that point was relevant. Spiders: as far as we know, could be from our world, could be from another world, infest the Tain. Suggestion: from Dark side, infest Tain (their speed and ability to climb steep slopes could have been useful in getting away from Myrkrydia), and have probably been brought into our world by the Spider Cultists.
Martel.