When Link first met Darunia, he was upset because the cavern containing the Goron food source was overrun by Dodongos and had been sealed off by Ganondorf as punishment for refusing to turn over the Goron's Ruby (also known as the Spiritual Stone of Fire). Once he was cheered up by Link's rousing rendition of Saria's Song, he gave Link the Goron Bracelet and asked him to clear the Dodongos from the cavern. Once Link completed this task, Darunia rewarded him with the Spiritual Stone of Fire, an unintentionally painful pat on the head and made him his "Sworn Brother".
After Ganondorf conquered Hyrule seven years later, he planned to feed the Goron race to the dragon Volvagia, who was killed long ago by a Goron hero, but has been resurrected by Ganondorf. When Link completed the Fire Temple as an adult, Darunia was awakened as the Sage of Fire, and gave Link the Fire Medallion. It is also revealed that Darunia named his son after Link. Darunia then helps Link enter Ganon's Castle and destroys the Fire Barrier. He lastly appears with the other Sages (only without Rauru and Princess Zelda) on Death Mountain. Saria is seen sitting on Darunia's head.
Several centuries later, a mosaic stained-glass window in Hyrule Castle depicted Darunia, along with the other Five Sages.
The mountain town of Darunia was later named after Darunia.