She was an Orbanian Urrone specializing in naquadah reactor technology. Kalan escorted her to Stargate Command so that she could help the SGC design and build their own stable Naquadah reactors. Merrin worked with Major Samantha Carter, who introduced Merrin to the concept of drawing. Merrin used her new skill to create cross-sections of a reactor which Carter could use to create a computer model of the reactor.
When it was discovered that Merrin would undergo the Averium and thus cause her to revert to a childlike state upon her return to Orban, Colonel Jack O'Neill took Merrin from the base without permission, and took her to a school in Colorado Springs so she could learn what fun was. Although initially reluctant, she learned to play and paint, and told O'Neill that she appreciated what he was trying to do. He was disappointed, however, when she told him that her new experiences made her even more eager to undergo the Averium. Before she went back to Orban, O'Neill gave her a large box of crayons.
After she had gone through the Averium, Kalan contacted the SGC and asked SG-1 to come back to Orban and they were amazed to see the former Urrone children (and indeed, most of the Orbanians) playing and drawing. They realized that Merrin had undergone the Averium because she had realized that the Urrone should be able to experience a normal childhood, and knew that sharing her experience was the only way to guarantee change. Merrin herself, however, was reduced to the infantile state of all former Urrone, and sat in a corner and drew with her crayons. Jack went up to her and took a crayon and started drawing with her, although she did not recognize him and corrected the changes he made. Merrin was later re-taught in the 'old way' along with the rest of Urrone children. (SG1: "Learning Curve")