Ibun was old before his days beneath Amon Rûdh were disturbed by Túrin Turambar and his outlaws, and thus his saga begins there. As he gathered roots in the wilderness with his brother Khîm and even more aged father Mîm. Túrin's men spotted the Petty-dwarves at dusk and, believing their business to be suspect, peppered the three with arrows, Ibûn hustled his companions homeward to no avail: Mîm ran too slowly, and Khîm took a fatal shaft in his chest. When Mîm's capture led the Petty-dwarf to extend hospitality to Túrin, Ibun grieved Khîm's death all that winter with Mannish intruders walking their halls. He spoke little, blaming his father for his loss of both brother and privacy, and sat in the shadows brooding. Spring pulled him outside again in Mîm's company to harvest the roots from which earth-bread was made. This time he was captured along with Mîm by Orcs, As ransom for their lives, Mîm led their captors along the secret way into Bar-en-Danwedh. Túrin was captured, the outlaws routed, and the Petty-dwarves left unharmed in possession of their home.Ibûn watched while Mîm made his jealous attack on Beleg Cúthalion the Elf, still silent while his father fled Amon Rûdh. The secret of the Petty-Dwarven hold had been broken by the Black Enemy. Ibûn packed a sack provisions and left the now vulnerable halls later that evening. He sought his mother's kin, and dwelt with them for many years. Ibun saw his father once more. Hearing rumors of an Orc or a Troll living within the caverns of lost Nulukkizdín. he traveled to Nargothrond to discover Mîm lurking there amidst the abandoned treasures of Valinor Over the course of seven days he repeatedly urged his father to depart the fouled lair before the Dragon's curse returned to roost. Mîm refused, and Ibun bid him a stem farewell, claiming a share of the Elven jewels rolling under the stalactites as wergeld for his father's certain death. With this inheritence, Ibun founded the holding of Ibunites named Narukgindín (later Cromm Bráighe).