The seven of them met at dusk in their hideout. The empire of their civilization constructed many such places of course, found all over the Heartland, strewn about and in their purity reflecting the sun's rays by day and casting great shadows by night. But the abaseli of the Ylorsel has been created by the order of the seven alone over many years. None save them know about this place, not their kin, not their arpena, much less any pellani from the other provinces. They alone held the key to this tenebrous secret, and a secret it shall remain, for even if the practices of the black arts are generally permitted and not really frowned upon, the seven strive for greater power than this. To cast down the shackles of mortality and ascend to godhood.
Of course there are other ways to attain such things as indefinite life. But the order decided that a conglomerate of foetid undead would be wholly counterproductive as they commanded the things from the realms of undeath, not be those creatures. There are rituals to achieve mouldy immortality, none of them at all favourable, they ascertained. None but one of which even they lacked the knowledge to conduct it, for it has been hidden from Mundus since the dawn of creation. Nevertheless, the seven concluded, it shall remain hidden no longer, hence they've constructed a place devoted to an antediluvian malignity. A being so ancient not even Magnus remembers, although he was the one to cast it out and seal the gate in times past, long before Lorkhan deceived the Et'Ada to give themselves to mortality. But the seven found out.
All of them have met a long time ago, during the very creation of the empire that presently reigns, constantly at war with man for control over these lands.
It was by pure coincidence they've worked together. All of them avidly conducting magical experiments in solitude before they happened to resolve to attend the academy in Cyrodiil in pursuit of greater knowledge, each of them highly proficient in one school of magic.
The first, a dangerous destructionist of immense power, the second a skilled illusionist, deceptive and sly. The third discovered a talent for the art of restorative white magic whereas the fourth reveled in chaos and bloodshed on the many battlefields the wars provided by conjuring various Daedra from the planes of Oblivion. The fifth, also a proficient herbalist, delved in the art of transmutation and alteration to morph and form the surrounding world as they saw fit. The last two, however, used other kinds of magic that were not known too widely and, as they should later discover, would yield great, if anomalous, results when combined. For the sixth did practice unholy blood magic, the seventh and final member of their coven would with legendary skill perform the dark art of necromancy.
Such were the ways of the seven and so it was they've found one another, their paths crossing, swirling around each other, inadvertently intertwining until at last they studied the arcane arts together.
All of them pursued unparalleled greatness, to rise above the Els of their kind. But these ambitions had to be concealed, for their kings feared usurpation, at any time ready to mobilize an army in the event of a coup.
So it was the seven formed an order, its name lost to time and untold myth, studying in secret, away from prying eyes and inquisitive minds. To this end, they acknowledged in their near infinite wisdom and intelligence, a place far away from possible spies was in order and caves were quite unsatisfactory for their murky dampness and all the soot and dirt contained within these hollow hills and stony cavities. To this extent, they resolved to dig deep in order to create their very own sel, only accessible if one was either a marine lifeform - or a skilled magician to draw breath when submerged, for the entrance to their fane lay deep beneath the surface of the luminously reflecting liquid that was so abundant around the central island. Furthermore, they thought quizzaciously, this act does not miss a mocking quality of political defiance, forbidden witches and wizards right under their master's noses.
By moonlight they would gather, forming dubious conventions with grim portent because, as they were quick to take note of, combining certain spells, rituals and incantations together would result in untold horrors and awesome primordial forces down there in the dark.
In time, scribbled notes pertaining to these discoveries were written, in great enough number to fill heaps of volumes with grievous knowledge, as it turned out that mixing the correct magical arts would open up doors to infinite possibilities. And although all this has taken place in times long past, it is whispered these horrible scrolls and scriptures still exist somewhere, obscured and cast in seemingly impenetrable shadow, unknown to man or mer. Some of these would eventually be found by just the right person, however, along with a deathly artifact.
Soon, the seven would stumble upon ancient legendry during their studies. Myths of portentous caliginosity that were hitherto lost to time. This was when their abaseli were being devoted to the solid night and called the Ylorsel.
And on this night, the coven met in their accursed halls as the starry phenomenon that would later be called the Necromancer's Moon shone darkly and a black mist loomed forebodingly on the horizon.
The order of the seven gathered in their cyclopean central chamber, in the inner sanctum of the Ylorsel, in which they stood in bleak darkness, circumjacent to an altar fashioned from grey stone, dimly lit by luminescent welkynd stones, tinting it in a pale cyan radiance.
The seventh held a book, ordering their associates to prepare for the ritual. Hereunto the seventh and the remaining six produced one black soul gem each from their opulent, hooded robes of white and gold in which they were clad, holding them before their respective chests and made them hover chanting the words:
"Lorcan, racuvarvoy an Ehlnada, nou balais delle tarnabye vey abatarn av Ylorene".
Hereat the gems radiated with light creating anti-luminescence, a prehensile abyss of unlight forming a crooked beam connecting the now quivering stones, still afloat, with the mages' hearts, staining their garbs, heretofore white, with a coal-like substance that appeared to eat and claw itself into the fibers.
In frigid darkness, the evident leader of the group continued the invocation, uttering words that made the air vibrate with primordial might when spoken:
"Sou belle bala lattia va cey! A ad'soon sou maltaelia ry synd ne ad'soon! Moragavoy an angua anyammis ye dellevoy ge anyamma va nagaia oio! Tye amaraldane Lalornir, ye as tye morielle A racuvar ehlnada ye joran sercen! DELLEVOY AN EDE VEY ANYAMMA, LARU'ME SOU GRAVIA HA'PHYN!"
Upon these terrible words being spoken, the hall was flung into abyssal nothingness, space and time seemed to bend, the very fabric of reality twisting and contorting in cruel, unspeakable fashion. A vitreous appearing, up to that night obfuscated hell revealed itself, a dead, empty vista, superimposed on current reality and the Mundus. In the distance, horrid and grim, there emerged a shadowy entity engulfed in smoky mists and anthracite fog spilling from an unnameable circular void, ejected into space in strange colour and queer incandescence.
The ensuing voice tore the bounds asunder with thunderous calamity.
"A EPE DAGON; A EPE NAGAIA. SHANTA, KYND. SOU CYLOR. CALVOY AN CYLOR VEYN. SOU ANYAMMABIS SUNNABE. HECA, KYND! NEMALAUTAVOY VA AN CEYALD!"
The ground quaked, the walls caved in. Water flowed unrelentingly through the cracks filling and flooding the space the seven were situated in. In that same instant, the black soul gems rose up into the air, gently approaching one another, merging together upon touch into a hideous artifact from beyond the veil. And by its power it was the souls of these men and women were ripped from their host's bodies by a preternatural might, crashing into the gem, thereby passing through, passing the opened gate. In this realm, their life force dissipated, transformed into ghastly glowing crystalline entities, undying and eternal, destined to govern this otherworldly place of damnation and purgatory.
Ever since, they've gathered souls by tricking mortals in infallible servitude to their deity, unknowing that they've been deceived themselves, at risk of fading into emptiness should they fail.