Its age indicates that it was purposefully made during the creation of Man, but only mentally manifested within mankind's Second Age.
For unknown reasons, the scholars of Genations would abide by its contextual rules that emphasized the watery traits of darkness, but much like its booming presence of both the unknown and its raw ire, the slab speaks itself unwillingly to those that peered through the dark churn.
“Even if humanity itself were a mere speck of nothingness, the everlasting grace that was bestowed upon mortals and the higher kin is nothing short of wonder. Curiosity once destroyed, and so it was that rules were inscribed. Somewhere, someplace, but no one knows where or on what. Whatever the scholars deciphered will forever remain unknown. Such is its rules, and its followers.” – The First Abomination