Excerpt from "A Dissertation on the Realms," by H.R.M. Thansor.
Chapter 7, introduction. "Though much is known about the first and second realms, information about the Third Realm and beyond grows increasingly slim. While Darsendor intersects with Calsin every single night, Torsorn is only accessible once per year. It is a beautiful land, and for that reason, I think that myself and many other realm mages wish desperately that it could be closer.
Torsorn comes into alignment with Calsin every year upon the winter solstice. From sunrise that day until sunset, if a portal is cast, an individual may enter into a land that, without a doubt, may be considered paradise. Lush trees rise into a purple sky, ripe with fruits more delicious than can possibly be described on paper. The animals there, oh, how glorious! They are creatures of beauty, animate flowers and vines that play with explorers as if they are pets. None have ever shown a hint of hostile intent.
Exploring Torsorn, though, has proven to be nigh-impossible. While portals may be cast from anywhere in Calsin, all will lead to the same location, known as Landing Grove. An uninspired name, I'm well aware, but the mages who first discovered the realm were far from the most illustrious. The location is a simple break in the expansive jungle, a small plot of grass perhaps one hundred feet in all directions. Once in Landing Grove, if a portal is cast back to Calsin, it will always appear at a similar point, known fittingly as Torsorn Grove in Elsinor. Thus, exploration of Torsorn is limited to the distance that a mage can travel in a single day.
Of course, the logical question that arises from this situation is simple. Why not simply have a mage stay in Torsorn for a year, make observations, and then come back the next year when the portal opens? Surely a much greater wealth of knowledge could be absorbed? In theory, yes, this would be a grand plan, and has been attempted no fewer than a dozen times. The first two mages that attempted it simply were never heard from again. When portals were re-opened the next year, they were nowhere to be found. The next several mages were all accidental, individuals who were either unable to send themselves back or chose not to. In any event, they have never been seen again, nor have subsequent expeditions been able to find their whereabouts.
Future attempts, in which mages planned on staying at Landing Grove for the full year to establish that it could be done, have been met with equal success. Mages brought journals, with the intent of documenting everything, so even if they fell ill, their words would survive. None of the journals have ever been found. The most recent attempt was the most successful of all, though even it wasn't a resounding success. The mage in question, a man named Vorius, entered Torsorn with the other mages, took a rock, and made a mark on a large boulder. He stated that he would make a mark for every day he was there, thus allowing future mages to determine how long it took before any castaways perished or vanished. When the new explorers came the next year, there were exactly three marks. Since then, the idea that an explorer might be taken so suddenly has kept all others from making such an attempt, and rightly so."