| Category | Caverns |
| Continent | Brucrumus |
| Region | Menortamon, Unaraggumak |
| Map | Kizan Line |
The Brother Tunnels, or Kronul Umthos in Dwarven, are expansive caverns and tunnels spanning across the northern Underdark sectors of Khelan and into Xalyth. The tunnels were significantly extended during the course of the First Kizan War. After fifteen arduous years of construction, a vital communication link was established between the dwarven cities of Rumaktharga and Dabul-Gind. These subterranean passages are widely believed to have been the critical factor that enabled the dwarves to triumph over the elves in the First Kizan War.
In 1591, construction commenced on the Kizan Line, a railroad that substantially improved transit between Fargimdal and their eastern ally.
Kronul Umthos extends approximately 160 miles from east to west, comprising a vast and perilous expanse. This region is actively patrolled only near settlements and along the Kizan Line. The most formidable adversaries within this domain are the death giants of Nemestyxe.