The Arcaena were a Human religious sect who believed in the preservation of knowledge from a coming (unspecified) cataclysm. One of their members was Heslant the Monk, who produced the Domia abr Wyrda.
Jeod also joined the Arcaena when he was young and looking for a cause to serve. He wrote an account of Eragon and Saphira and the rise of the Varden. When he was finished, he sent it to Ertharis at the Arcaena Reliquary in the Spine. This account would be included as a few new chapters in the Domia abr Wyrda.