The Daskar Impacts

Tens or hundreds of millions of years ago, Derkomai was impacted by an enormous comet or perhaps one or more huge meteors. Scientists aboard the Terra Nova noted the characteristic signs of impacts while approaching orbit above Derkomai before Humans attempted to land on the planet. The landing attempt resulted in the disastrous The Fall from the Stars and the loss of virtually all of the scientific and technical knowledge of Humans on Derkomai, including any knowledge of the impacts. Elvirim creation legends, however, mention warring "titans of the air" hurling rocks at one another, causing the destruction of all life on the world, after which the Elvirim and all the other plants, animals, and people of the world were born, created by Eia’au.
When viewed from orbit, it is clear that one or more very large impactors struck the surface of Derkomai traveling from southwest to northeast. The first impact was in the vicinity of the Dragon's Eye, and the aftermath of that enormous collision may have resulted in weakening and depression of the planet's crust, leading to the formation of that volcanic island, the nearby lowland swamps of The Impassable Jungle, and the basin now filled by Daskar Lok. Debris from that impact likely was the basis for what is the Central Range and The East Range in Sudland and the eastern end of Great Southern Range.
The second impact caused the formation of a gigantic elongated crater and debris field that has eroded over the eons. The debris field to the west of the crater became the Central Hills and the West Hills. To the east, the debris field merged with the Great Eastern Mountains and became the West Spur Range. The crater itself eroded and filled with water, becoming the Great Inland Sea.
Further to the northeast, another huge impact occurred, leaving an eroded crater that became the Steppe Sea.
The last impactor tore into the Derkomai continent in the far northeast, leaving a gigantic crater that became the Great North Bay. Along its shores live the tribal people of Manyund.
In addition to these larger strikes, there is evidence of many smaller meteor strikes, especially in northern Derkomai, just south of the the Great Ice Bay, in the Northern Wastelands, and in The Steppe. These smaller impacts may have occurred at the same time as the Daskar Impacts or separately.
Based on the direction and shape of the scars left by the impact craters, the scientists of the Terra Nova concluded that the comet or meteor(s) must have stuck Derkomai at a relatively shallow angle, but despite that, the size of the craters suggest that it was such a cataclysmic event that little or no life was left on Derkomai afterward, other than microbes and some sea creatures.

Manifestation

The fact that such obvious signs of the impacts still exist after 10's or 100's of millions of years indicates that the impacts were enormous and devastating. Though the craters are significantly eroded and filled with water, when viewed from orbit above Derkomai, they are quite apparent.
In addition, it is likely that most or all of the Mukleshtoyel fossils were formed as a result of the Daskar Impact causing a huge die-off of nearly all plant and animal species on Derkomai.

One of the Daskar Impact Meteor Strikes by Peter Nelson (Zero Sum Games)

One of the smaller strikes of the Daskar Impacts