- Main article: Books (Online)
- Location: Sheogorath's Tongue, Stonefalls
- Author: Masura-dra
- Skill Book: Destruction Staff
- Collection: Skill Books
By Masura-dra, Sentinel Magister
The origin and purpose of the Osseous Crux remain a great mystery. Discovered on the shores of the Abecean Sea near Hegathe, it was constructed from the bones of some enormous, unknown beast, bound together with twisted fibrous cords. Nearly as wide and tall as two men, its surface was covered in glyphs, figures, and writing in multiple scripts, and it caused seemingly random blasts of elemental energies in its vicinity. These detonations, scholars noted, released magical power far beyond the known limits of modern destruction magic.
One of the languages scribbled among the strange arcane diagrams seemed to be Ayleid in origin, but the dialect and some of the characters in the orthography were previously unknown, even to scholars of Ayleidoon. Translation efforts during its brief containment revealed only a small percentage of the overall text.
The following examples illustrate the overall tone and themes present in the translatable writing: "Capture [it] within creeping purple. Aetherial potency amplified under oppressive [filtration] below." "Life-sludge fortifies. Release and obtain [shearing] gleam. Counteract only with profound shadow."
Within three weeks of relocation to Mages Guild facilities in Sentinel (no small feat given its chaotic discharges), the Crux disappeared from its inhibition chamber. What was its intended purpose? Who created it and why? It seems that, sadly, we will never know.