|Locations of interest|
|First appearance||Myst: The Book of D'ni|
The Terahnee and D'ni languages apparently had sound and grammar shifts parallel enough to remain mutually intelligible, despite the long separation and massive differences in culture and values.
The Terahnee culture is extremely complex. It involves a system of Lords, that rule over individual areas. The entire Age is ruled over by a King. Terahnee was a cruel civilization that was based on the slavery of entire Ages.
A book to Terahnee was kept by the D'ni people, the minority who didn't follow the Terahnee, but opted to follow Ri'neref to a new Age and follow their own values. The book was sealed in a vault. Centuries later, Atrus discovered it seeking to find survivors of the D'ni.
The king befriends Atrus and his companions because they are from D'ni. At first Atrus and his friends believe that Terahnee is a culture for them to admire, and consider moving all the D'ni people to it; but later discover that Terahnee is actually built, and operated, by billions of slaves taken from their native ages. Shortly thereafter, the ruling class of Terahnee are exterminated by a pandemic. The weakness of the master people prompted a bloody slave revolt.