Originally from Amsterdam, Holland, along with her younger brothers, the twins Max and Sam. Lyn is the reincarnation of Kisara, keeper of the Blue-Eyes White Dragon, and as such, has or had the ability to summon said beast. This power first manifested when she was younger, and, upon recognizing the BEWD, scraped together enough money to take her and her brothers to Egypt, where she met Ishizu Ishtar, who taught her about her powers and gave her a job as assistant curator. During the events of Battle City, she stayed behind in Egypt while Ishizu went to Domino City, but when Dartz used the power of the Orichalcos to manifest Duel Monster Spirits in Domino City, she and her brothers flew to Japan to investigate. Unfortunately, by the time they arrived, the Duel Monsters had gone and the Duelists had left for America. She and her brothers eventually found their way to the mountain shrine owned by Genkai, where Yusuke Urameshi was training for the Dark Tournament. Lyn, Max, and Sam were staying at the shrine when Yusuke took Yui Tsubasa and her friends (including Mokuba Kaiba, who had seen her summon the BEWD during the Rajita attack at Kaiba-Con) for a visit. Mokuba eventually introduces her to Seto, whom she has to convince to use his newly-acquired Armor of Critias to help people other than himself.

She is the top female duelist of Japan and one of the four elite duelists in Domino City (with Yugi, Kaiba, and Joey). After impressing Maximillion Pegasus with her knowledge of Egyptian mythology in the movie, she was appointed the head of I2's Egyptology department. She and her brothers live with Seto and Mokuba at Kaiba Manor at least, they did until the Paradais Knights blew it up. Lyn and Seto are currently in a relationship.