The Great Kayarsus is a vast system of mountain ranges that forms the eastern frontier of Eärwa, stretching for several thousand miles.[1]
Siöl, the oldest and greatest of the Nonmen Mansions, lay under the northern Great Kayarsus, guarding a fortified series of passes leading east into the continent of Eänna. According to some historians, Siöl itself is the Gate of Thayant, the shattering of which marks the beginning of dated human history and the commencing of the Cûno-Halaroi Wars.[2]
Aside from the Gate of Thayant, no other major pass linking Eärwa to Eänna is known to exist, although one in the vicinity of Jekhia in far north-eastern High Ainon is likely, given the history of that region and the cultural influence of the Xiuhianni, the only one of the Five Tribes of Men to remain in Eänna.