The Caverns of Twilight

A system of caves north of Donara. According to legend it is a place where items so powerful as to disrupt the balance of the world are placed (see artifacts). Inside the Caverns the pocket dimension of Oblivion is located. Oblivion is a place where time stands still. 
Map III-w
==Description==
Some attribute these caverns in the Morgahlte Massif to Kirion, some to all the gods, and some claim that the world could not be without it. It is a place of balance, for here are stored many great artifacts. The Twilight Caverns has a dampening effect on all magic, and artifacts are placed in a kind of sleep. Those who would rid   themselves of an artifact need merely deposit it in one of the small caves. By magic, each cave may holds one item of power. But the artifact is not lost forever, as a determined adventurer may claim it again. But he must overcome three challenges, the first is a guardian of the cave. If he defeats this monster, he must overcome a second challenge whose nature depends on the item he seeks. Sometimes it is another monster, sometimes a riddle, but the challenge is somehow related to the artifact. Lastly, he must fight himself. This deters many treasure-seekers, as one must fight alone and the body may never be found. If successful, the adventurer has the dubious honor of owning an artifact.
Also within the area of the caverns is a place called Oblivion. Oblivion is a place were persons are sent and forgotten about, only to return many years later. For them, no time will seem to have passed. Originally this was a divine punishment dealt out by priests and sometimes the gods themselves. Later, wizards learnt to duplicate the effects in a spell. If a friend is sent to Oblivion, another hero could go there, calling his name. The hero must then fight a guardian, and if successful, the friend is freed. Otherwise, the friend is returned to the original spot, but this could be centuries later. Some scholars believe that all the Caverns of Twilight are like Oblivion, meaning that artifacts left here somehow wake up and return to Bandagora proper, even if no one comes to claim them.