Construction beginning/end
The Grengadeen, prior to rising to power, construct the Tower of Agorathdorn, in which they study old magic.
Before the reconstruction of Onar and the formation of the empire, the Grengadeen were minor lords controlling a portion of land adjacent to the Onar Stretch. Here, they settled the Tower of Agorathdorn. From the tower, they investigated magic and were eventually among the first humans to understand brands. With these powers, they became the first sole rulers of the Onarian Empire.