The Years of Black Rain was a period in the history of Rothurland in which dark, oily rain regularly fell. For six years, from Y8121* to Y8127*, most normal rains ceased as storms brought the black liquid instead. Water became contaminated, plants and animals died, and massive fires burned large swaths of the landscape.
Not all of Rothurland was affected equally in this time. The black rain fell throughout the region, but especially in Icepeak Island and around Eyjara Bay, as well as to lesser degrees in the inland forests, south of the Sentinel Peaks, and in the southern part of the fjords. The farthest north parts of Rothurland, including the northern fjords and the Svell Islands, were largely unaffected. Some of the rain also reached the western-most parts of Laurentia.
The black rain caused one of the largest mass migrations out of Rothurlaund in its history. As crops failed year after year and animals died en mass, large numbers of colonists departed their homelands for better lives elsewhere. Some settled in the Coldwind Islands or elsewhere around the Alkyonides Sea, while others moved farther afield, including to the western and southern coasts of the Chaska Sea. A few made it as far south as Hinthial, where they established small villages near the elven city of Aurina.
The cause of the black rain is uncertain, as is its sudden beginning and retreat. Some in Rothurland believe it to have been the last blood of Ubilai, thrown down by the other gods either carelessly or as punishment. Other theories and tales are shared as well, yet none can be proven or stated conclusively.