Ucin was the son of the bard Sinuphel of Hildorien. He was born during the late First Age. His father was Khazí, the younger son of the dwarf-king Drúin. Along with his twin sister Ulaphel he was the first of the Umli. Born in Hildorien in the roundhouse of Lord Cantapher, Ucin was removed to Urd in the northern Middle-earth about three months after he was born. Ucin's hildo relatives were frightened by his uncomely appearance (to them he was hideously ugly) and believed that he was a monster. They had no idea or concern for the fact that his spirit was untainted. Ucin was raised by his mother at a cave-home in the deep valley of Ushashir, not far from the icy waters of the Sea of Illuin. Both he and his sister were well-educated despite their exile. By the age of seven, he knew three languages and understood stars of the northern skies as well as any Elf. He became an excellent swimmer, an able water-man and a cunning hunter. His precociousness enabled him to survive the premature demise of his beloved mentor and mother, Sinuphel. When Ucin and Ulaphel were only fourteen the great grey-white cold-drake Lamthanc came out of the Iron Mountains in search of food and riches. After slaughtering many of the Avikangsdar tribes he entered Urd where he occupied a lair. His appetite was such that he ate most of the mammals that lived along thr eastern coast of the Sea of Illuin and his presence quickly threatened the nearby Lossoth. The brave Sinuphel, an ally of the Forodwaith, confronted the creature, who tricked and then slew her. Lamthanc then ate the fallen hildo-bard. Ucin vowed revenge and awaited Lamthanc at a spot which was plentiful in seals. The drake struck there about one week later and Ucin tracked the beast to its lair. In the ensuing struggle the youthful Umli severely wounded the drake with his mother's harpoon. Lamthanc fled northward over the mountains and into Uab lands. Ucin occupied Lamthanc's lair. While unable to recover his mother's body he made his new home a shrine to Sinuphel's memory. Twenty years later he wed a dwarf-maiden named Báis, daughter of the dwarf-lord Broin of Drúin's Folk. This marriage was in keeping with the ancient Melkoric curse that afflicted all of Sinuphel's line that "Cintapher's wife and all her heirs shall join in love against their law and produce half-folk who shall be shunned by second born and dwarfborn alike". Together Ucin and Báis had three children: Ucas, Urái, and Ulaphel II. These opffspring spawned the Ular-shi, Shasir, and Ushahir Umlati.
Tolkien's writings seem to make a real blending of Hildo and Khazâd blood highly unlikely. Therefore it seems that the Legend of Ucin and Ulaphel must be considered false, and Ucin's sire was in fact not Khazî but a mortal man, it must have been legend or rumors that made the people of Hildorien wrongly suggest Khazî to be his father. Also it seems unlikely that Ucin's wife Bais was in fact a dwarf-female. She may have in fact been a Hildo girl raised by dwarves. After all, if the origin legend of the Umli is considered a legend - and nothing else - this would make the Umli just an exotic Easterling-people. Maybe influnced and taught by Dwarves to some degree (as Tolkien's writings suggest some early contacts of both races) but not true half-bloods.
- MERP: Lords of Middle-earth Vol III: Hobbits, Dwarves, Ents, Orcs & Trolls