Excerpt from "A Dissertation on the Realms," by H.R.M. Thansor.
Chapter 13, introduction. "The number seven has often been denoted as the luckiest of all numbers. Perhaps it is for this reason that the Seventh Realm, Besdir, is the final realm that mages have managed to travel to. Despite it being a lush and grand land, the fact that it can only be entered once every hundred years has significantly prevented exploration of this realm.
When Besdir begins to come into alignment with Calsin, it is extraordinarily obvious. Lights begin to spiral through the night skies, often accompanied by comets and shooting stars. When the realm becomes available, a brilliant new star appears in the sky, a powerful light nearly as luminous as the full moon. For exactly two weeks, mages are able to enter and exit the realm at will, after which, the star vanishes and life must return to normal. The last alignment of this realm occurred a mere five years before I became a Realm Mage, which means that I will likely not be alive when it happens again. Nevertheless, it is my duty to report on it, and so I will.
The star that appears over Calsin always appears over the Inland Ocean, near the exact center. At this point, directly below the light, a beam shines down into the water, a tangible stream of light. Sailing or swimming into this light will result in transportation into the oceans of Besdir. A corresponding beam of light shines down from a matching star in Besdir, which can be sailed through in reverse to return to Calsin. If sailing in a large vessel, it is advisable to send pulses of light or other forms of warning ahead of you, to avoid major crashes or shipwrecks.
Once in Besdir, there are several nearby islands that are within sailing distance. All of them are tropical, and have very similar foliage to Sournous. Animal life is abundant, though only in the form of nonmagical creatures, most of which are quite similar to the common wildlife of Calsin. The first expedition through the portal focused on these islands, of which there are five. All were explored quite easily in the few short weeks it was open, yielding nothing of extraordinary value. The second expedition tried sailing beyond the islands, where a vast continent was discovered. Only a single day's travel from the portal, it was a simple matter to make it that far, explore some of the land, and make it back. Several sets of ruins were found, along with ancient writings (all of which are now housed in the Wizarding Academy's vaults, where they still undergo translation). However, this simply isn't the interesting part about this realm.
No, the truly fantastic aspect of Besdir is the metal creatures. While other realms have buildings made from metal, this realm truly has animals and beings made from pure metal. Most of them are simple creatures, animals and such, living among the more natural life in harmony. A few, though, are fully sentient beings made from pure metal. According to reports, they appeared and immediately charged the exploratory group, killing all but a few involved. Since then, all encounters with them have gone poorly. With their bodies made from pure metal, it makes it impossible for our simple weapons to harm them, and even magic often proves ineffective (though it should be noted that lightning spells seem to work quite well).
All told, with only four total expeditions to Besdir, and the threat of hostile attack every time, precious little of the land has truly been explored. With the documents still awaiting complete translation, we may never know the history behind these metal creatures."