Republic of Hahd is ostensibly an underwater country below the tip of what was once the Dallesian peninsula. Its government is not recognized by any under Imperial authority. As its people, also called Hahd, have made no trouble whatsoever for anyone in history (save once), this same government has never been contested, either. That Hahd is documented here at all is because of the singular time the Republic had an effect on Tamrielic affairs (which also marks the first time any of the known peoples had heard of it), and by some kind and enabling words of a mapmaker.
In the early third era, the Altmeri Keepers of the Orrery of Firsthold suddenly paid tariffs to the Empire on behalf of the Republic of Hahd for "submersible exports of mnemolichite to the Emirates of Nahd". While the Septim Regime was glad to receive the not un-trivial amount of the tariff expense, it did demand to know three things: one, what and where was Hahd, two, what exactly was mnemolichite, and three, what and where was Nahd.
When the Altmer had no answers to any of this, the Ruby Throne grew suspicious and mustered its Armada to make sail. An offended Alinor responded by withdrawing all of its sunbirds from the Pyandonean line to meet the Empire. Just before emissaries from both sides of the imminent battle were about to give up disentangling the mounting myriad of accusations, a book from Hahd arrived by an undisclosed courier to "explain everything whereby these hostilities may cease."
This book was studied by a joint committee of Altmeri and Cyrodilic officials and watched over by an impartial Psijiic of the recently-returned Artaeum. It described the Republic in little detail, only enough to give its supposed location far below the waters of Dellesia. The committee agreed that such a habitat as depicted in the book was impossible (for one, the Hahd described themselves as air-breathers that never needed to break the surface of the sea). This unlikelihood was eventually cemented as an outright falsehood by civilized dreughs living near that region. They had never heard of the Republic of Hahd, and no intellectual of Tamriel ever argued with the cepholomer at that time.
On the separate cases of the Emirates of Nahd and the mineral called mnemolichite, the Republic's explanations for both were the same: they were figments of imagination, a kingdom and a treasure made popular in the Republic by their recurrence in its many fables, underwater campfire stories, and stageplays.
"We are not a very creative folk," the Hahd admitted, "But we always enjoy hearing about the fantastical heroes of sandy Nahd and the wondrous powers of mnemolichite because of the delight that their impossibilities bring to our hearts."
Obviously, what the book failed to properly explain was the impetus for the payment of Firsthold tariffs in the first place. After a fifty-year study of the book and its Republic, the committee went back to analyzing the only thing that might shed light on this matter: the financial logs of Firsthold and those payments sent from the Orrery Keepers to the Imperial Treasury. By this time, however, both the pertinent parties— the Altmeri paymaster and the Cyrodilic Clerk of Tithes Submersible— had long since been replaced, leaving only their records of the by-now bewildering transactions behind. Another fifty-year investigation of these materials ensued. In the end, unraveling anything more about the Republic of Hahd and its mysterious manipulation of Firsthold was deemed futile by both Cyrodiil and Summerset; the surviving members of the joint committee were finally dismissed and sent home in 3E230.
That same year, the Isle of Artaeum disappeared again. Reluctant rescue operations in and about the Blue Divide discovered no survivors of this new version of the phenomenon and no signs of misdeed mundane or magical; all agreed that the Psijics were up to their own tricks again, and the advent of the Mages Guild made this an unworthy endeavor to pursue further. A few days later, however, sailors aboard the NWN frigate Colleen, on its way back to the Iliac to put down more Haymonic insurgency, discovered a book in its dragging nets. It was entitled, "The Dervish of Dellesia and the Mnemolichite Maid." Quite by chance, the captain of the Colleen, Davidius Eel, was a great-nephew of one of the members of the joint committee that had obsessed over the Republic of Hahd for a hundred years.
Captain Eel began to read the manuscript immediately, if only out of a blood-guilt to restore the unsatisfied honor of his ancestor. He was only a few paragraphs in when he realized, to his astonishment, the book's true nature. It was not, as its title might suggest, a fable about Nahd from the denizens of Hahd, but rather a fable about Hahd from some unknown writer of Nahd. The eponymous dervish was some kind of "air-breathing sea-soldier, formerly of the Republican Guard", who was either protecting or wooing "that maiden to first hold the star-minerals of heaven". Perhaps most troubling was the author ("a humble Nahd of Nahd") and his nearly rote-written preface, which clearly, if uncreatively, indicated that the book was part of a large series or maybe even a shared universe, whose twin anchor points were always the same: an obsession with Hahd and the "powers" of mnemolichite. The latter was never adequately explained in the manuscript, nor has it ever been.
It is the belief of this Survey Agent that any description of the true nature of mnemolichite was as unneeded for the story's intended audience as an explanation of the sun's true nature would be for a citizen of Tamriel. It was also the belief of this Survey Agent that the regions of Hahd and Nahd not be written of here at all, since no real answers of their disparate (?) peoples, lands, or cultural make will likely surface, and that that futility is not befitting of our society. It is to my great friend and colleague, Senior Cartographer Rinmaut, that I dedicate this lengthy passage to him and his words of convincing, "Those places that cannot be mapped, they should never cry avast to our pens to stop and try."