| Category | Depressions |
| Continent | Karterus |
| Region | Azrik |
| Map | Vetoubahr |
The Ratanur Trap is a profound chasm situated in the heart of Vetoubahr. It has long been shunned by the peoples of Azrik. There are no roads or paths leading into it, and a precipitous two-mile descent into a lake once haunted by aquatic demons is more than sufficient to deter the vast majority.
In the Demon Spawn War (89 GE - 269 GE), a rift manifested at the tip of Moredhel. This rift served as a connection to Kurun'Ush, a realm under the dominion of the demon lord Gorag'theg. Subsequently known as the Moredhel-Fihrgrell Rift, it opened on 3 Temporal 233 GE, with one side revealing an abyssal ocean and the other a soon-to-be flooded valley. After the initial deluge, the flow stabilized, forming a river of seawater that descended the valley and then flowed northwest, filling the Ratanur Trap before continuing onward to the sea.
In 237 GE, engineers under the Covenant general Abbathor planted a null mine, creating a counter to the Moredhel-Fihrgrell Rift. This second rift, situated beneath the submerged floor of the Ratanur Trap, was the Fihrgrell Drain. Upon its opening, the canyon drained, with the water flowing over in waterfalls, drawn through the Fihrgrell Drain and back to the abyssal world from whence it came. The river continued to flow out of the upper rift for eight years, confined to the valley before cascading into the rift at the canyon's base. When Thyrm sealed the upper rift with the The Frozen Titan, the influx of seawater came to an end.
Today, the base of this ravine is a briny lake, which owing to its profound depth, is regarded more as an Underdark domain than a surface feature. Lake Dynaer is the residual waters of Fihrgrell's maritime expanse that flowed through the Moredhel-Fihrgrell Rift.