The Twilight Dragon was a monster occasionally spotted in deeper parts of lake Nenuial, typically in the evening, with just a part of its head or back breaking slightly from the water's surface. What it might be was unclear to the Arthedain, because the creature certainly didn't act like anyone's notion of a Dragon. Its existence was doubted by some, since it seemed impossible that such a large beast could swim in a lake in the heart of Arnor for so long undetected. Even occasional incidents along the shore, some including gigantic footprints, were generally attributed to freak storm winds and drunken delusions. Curiously enough, the Twilight Dragon was just that; a female cold-drake. She was given the name Karikmorathur when she was spawned, somewhere in the pits of Thangorodrim in the deeps of time. Altered to breath water as well as air, she received the important task of laying and guarding a clutch of special eggs, twelve in number, in a cavern some two hundred feet below the water line on the western side of Nenuial. Karikmorathur was single-minded and subtle as Dragons went. She had little interest in treasure, and for the last several thousand years had made avoiding attention her primary concern. She caught fish, usually by night, and collected information about the outside world through subtle means, usually magical ones. She devoured Men rarely, generally under circumstances in which other causes might be blamed for the deaths. Certain Rites of Power could summon her to the lake shore; cultists who tried this and lesser mages who duplicated the Rites by accident could find themselves aided or eaten, depending on Karikmorathur's mood. One who visited Nenuial early in the 13th century of the Third Age got a respectful audience from her, and a muddled and disbelieved account of the meeting had drifted back and forth across Eriador repeatedly ever after. A summation of the tales was compiled and would result in the following story:
"A tall, black-cloaked Lord, it was said, accompanied by a few grim knights, rode down to the shores of Nenuial one grey morning and spent the day casting a mighty spell. That night, he walked to a high rock overlooking the lake and sounded a mournful call on a great horn, one such as might be used to warn off passing ships in a fog. A powerful answering call was returned to him from Nenuial, and a great, black-scaled head rose amidst the waves offshore. The Lord spoke to the beast, telling her of a new realm he had founded to the east, one that would be friendly to Karikmorathur. He was riding through the Dunadan lands he planned to conquer and could not tarry; the Arthedain were beginning to show interest in his travels, and he had no desire to justify himself to them. But he spoke to Karikmorathur of hope; the eggs she guarded would one day produce Dragons powerful offspring of many kinds and powers, and she would rule over this country. He promised to tell her when the Dunadan were weak enough, for then he would send her the magical key to the hatching of her brood. It was said that Karikmorathur bowed her great Dragon's head to the dark stranger, and after he left she returned to the depths renewed in purpose."