Lyn is the first female main character in the series since Fire Emblem Gaiden. Although her full name is Lyndis , she is referred to in almost all screens by her Sacaen name 'Lyn' throughout the game. The two names are generally regarded to be interchangeable, depending on who addresses her. She is 18 (15 in the Japanese version) at the beginning of the events of Fire Emblem.
Born in the Sacaen Plains, her parents—Lord Hassar, chieftain of the Lorca tribe, and Madelyn, daughter of Lord Hausen of Caelin—were killed by bandits before the beginning of the game. She was named after her maternal grandmother. She lives alone until she finds a tactician (the player) lying on the ground. Upon meeting him or her, she decides to follow him or her in the interest of training her sword skills. She then meets Sain and Kent, knights of Caelin who tell her that she is the granddaughter of Lord Hausen, the Marquess of Caelin, who wants to welcome her into his home (something he had refused to do when his daughter Madelyn eloped with a Sacaean "savage"). Along the way, she saves an old priest of a shrine that was attacked by mercenaries. In gratitude, he allows Lyndis to lay her hands upon the Mani Katti, a sacred weapon within the shrine. As it turns out, she is the only person who can draw the legendary sword, and the priest tells her to take it with her. Towards the end of the game, she receives a new sword called the Sol Katti which is not a true legendary weapon despite it bearing great power and being the "sister sword" to the Mani Katti.
On the way to Caelin, she eventually finds out that her grandfather is being poisoned by her granduncle, the power hungry Lundgren, who desires to succeed his brother by any means necessary. Upon reaching Castle Caelin, Lyndis and her allies defeat Lundgren's forces in a final battle. It is after this that Lyn and her grandfather meet for the first time. Though in a considerably weakened state, Lyn convinces her grandfather to keep fighting so that the two may live together and learn more about each other. Lyndis then stays with him at Castle Caelin until the events of the main story.
Unlike the other lords, Lyndis is not mentioned or referenced at all in Fire Emblem: Fūin no Tsurugi due to the fact that she and her grandfather Hausen were created specifically for the prequel. As such, it is unclear what happens to her in the twenty years between the two games, although her multiple endings present certain possibilities. She either marries one of the characters and gives birth to a child (Roy, Lilina, or Sue) that later becomes a character in Fūin no Tsurugi (presumably dying before the beginning of the game), or she would turn control of Caelin over to Ostia following Hausen's death, and then return to Sacae with one of her comrades.
Lyn makes a cameo appearance in Super Smash Bros. Brawl as an Assist Trophy.In that game, she is voiced by Lani Minella.
Normal (Lyn's part): Lyn now lives with her grandfather as Lady Lyndis of Castle Caelin. Under her loving care, Lord Hausen recovers, and now the two of them go for many walks in the Caelin gardens. On clear, dry nights, Lyn can be seen high atop a hill near the castle