What ended the cult was the partial exploration of the black realm of N’kai beneath the red-litten world of Yoth. According to the Yothic manuscripts, there was no surviving life in N’kai, but something must have happened in the aeons between the days of Yoth and the coming of men to the earth; something perhaps not unconnected with the end of Yoth. Probably it had been an earthquake, opening up lower chambers of the lightless world which had been closed against the Yothic archaeologists; or perhaps some more frightful juxtaposition of energy and electrons, wholly inconceivable to any sort of vertebrate minds, had taken place. At any rate, when the men of K’n-yan went down into N’kai’s black abyss with their great atom-power searchlights they found living things — living things that oozed along stone channels and worshipped onyx and basalt images of Tsathoggua. But they were not toads like Tsathoggua himself. Far worse — they were amorphous lumps of viscous black slime that took temporary shapes for various purposes. The explorers of K’n-yan did not pause for detailed observations, and those who escaped alive sealed the passage leading from red-litten Yoth down into the gulfs of nether horror. Then all the images of Tsathoggua in the land of K’n-yan were dissolved into the ether by disintegrating rays, and the cult was abolished forever.
Aeons later, when naive fears were outgrown and supplanted by scientific curiosity, the old legends of Tsathoggua and N’kai were recalled, and a suitably armed and equipped exploring party went down to Yoth to find the closed gate of the black abyss and see what might still lie beneath. But they could not find the gate, nor could any man ever do so in all the ages that followed. Nowadays there were those who doubted that any abyss had ever existed, but the few scholars who could still decipher the Yothic manuscripts believed that the evidence for such a thing was adequate, even though the middle records of K’n-yan, with accounts of the one frightful expedition into N’kai, were more open to question. Some of the later religious cults tried to suppress remembrance of N’kai’s existence, and attached severe penalties to its mention; but these had not begun to be taken seriously at the time of Zamacona’s advent to K’n-yan.
As the cavalcade returned to the old highway and approached the low range of mountains, Zamacona saw that the river was very close on the left. Somewhat later, as the terrain rose, the stream entered a gorge and passed through the hills, while the road traversed the gap at a rather higher level close to the brink. It was about this time that light rainfall came. Zamacona noticed the occasional drops and drizzle, and looked up at the coruscating blue air, but there was no diminution of the strange radiance. Gll’-Hthaa-Ynn then told him that such condensations and precipitations of water-vapour were not uncommon, and that they never dimmed the glare of the vault above. A kind of mist, indeed, always hung about the lowlands of K’n-yan, and compensated for the complete absence of true clouds.
The slight rise of the mountain pass enabled Zamacona, by looking behind, to see the ancient and deserted plain in panorama as he had seen it from the other side. He seems to have appreciated its strange beauty, and to have vaguely regretted leaving it; for he speaks of being urged by Gll’-Hthaa-Ynn to drive his beast more rapidly. When he faced frontward again he saw that the crest of the road was very near; the weed-grown way leading starkly up and ending against a blank void of blue light. The scene was undoubtedly highly impressive — a steep green mountain wall on the right, a deep river-chasm on the left with another green mountain wall beyond it, and ahead, the churning sea of bluish coruscations into which the upward path dissolved. Then came the crest itself, and with it the world of Tsath outspread in a stupendous forward vista.
Zamacona caught his breath at the great sweep of peopled landscape, for it was a hive of settlement and activity beyond anything he had ever seen or dreamed of. The downward slope of the hill itself was relatively thinly strown with small farms and occasional temples; but beyond it lay an enormous plain covered like a chess board with planted trees, irrigated by narrow canals cut from the river, and threaded by wide, geometrically precise roads of gold or basalt blocks. Great silver cables borne aloft on golden pillars linked the low, spreading buildings and clusters of buildings which rose here and there, and in some places one could see lines of partly ruinous pillars without cables. Moving objects shewed the fields to be under tillage, and in some cases Zamacona saw that men were ploughing with the aid of the repulsive, half-human quadrupeds.
But most impressive of all was the bewildering vision of clustered spires and pinnacles which rose afar off across the plain and shimmered flower-like and spectral in the coruscating blue light. At first Zamacona thought it was a mountain covered with houses and temples, like some of the picturesque hill cities of his own Spain, but a second glance shewed him that it was not indeed such. It was a city of the plain, but fashioned of such heaven-reaching towers that its outline was truly that of a mountain. Above it hung a curious greyish haze, through which the blue light glistened and took added overtones of radiance from the million golden minarets. Glancing at Gll’-Hthaa-Ynn, Zamacona knew that this was the monstrous, gigantic, and omnipotent city of Tsath.