Third Great Tolkeen Library
The city of Tolkeen contained three great libraries. During the siege, the Coalition uncovered the other two but by December of 109 P.A. the third library remained hidden, much to their chagrin. When the siege started many of the wealthy and privileged of Tolkeen escaped to the library to await rescue and safe extraction. Instead, two Deevil spies broke in, slaughtered everyone within and completely ransacked the place before being trapped in a makeshift temporal prison that also contained the Codex of Souls.
By March of 110 P.A. the library was completely empty. It appeared like a giant fire or explosion went off inside. The portals which were used to access both the library and the temporal prison were both gone, as was the temporal prison itself.