Esel (esel[contested]) was a self-taught D'ni historian. During the Fall of D'ni, Esel's father, a Master in the Guild of Archivists, fled with his family to the Age of Bilaris. Fearing that the destruction would follow them, they moved off of the main island to the backside of a smaller one, where their settlement would not be visible to pursuers. Esel's father died 12 years before Atrus began the First Restoration of D'ni, but not without first teaching him and his brother Oma all he knew about D'ni.
When Atrus first returned to rebuild D'ni with the Averonese, Oma, Esel, and their crew spied on them. Eventually, they decided that Atrus was doing the right thing, and joined his expedition, where they assisted members from the Guild of Stone-masons and other technicians, as well as working with the Maintainers' suits, translating the texts of Linking Books to see if they were safe, and translating the ancient writing in the Temple of the Great King.
Esel, the less talkative of the two brothers, is decribed as being tall and having dark hair and thick, dark eyebrows locked in a permanent frown.
It is believed that he lived out the rest of his life on Releeshahn.