Character description
Lyn is the second female main character in the series and the first one since Fire Emblem Gaiden; she is the only one of three main lords of the game who does not appear in Fire Emblem: The Binding Blade. 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. At the start of the game, Lyn meets the player (who acts as a tactician in the game); after assisting her in defeating bandits near her house, Lyn decides to follow him or her in the interest of training her sword skills. Along the way, she meets with many different characters, some of whom join her on her way; additionally, she later learns of her true fate of being the sole heir of the Caelin throne, and vows to defeat Lord Hausen's brother of Lundgren, who plans on taking the throne for himself. Lyn's eleven chapters primarily serve as a tutorial to new players, and her mode also had the unique feature in that it was the first time in the Fire Emblem series where characters can lose all their HP, but still be playable later in the game.
Lyn later returns for both Eliwood's and Hector's stories; initially driven out of Castle Caelin by the Black Fang, she's assisted by Eliwood and Hector to regain the castle, and she later continues to travel with them, with plans to destroy the Black Fang and their leader's, Nergal, plans to bring dragons back to life.
 In Super Smash Bros. Brawl
 As an Assist Trophy
In Brawl, Lyn appears as an Assist Trophy. She charges her sword, and then teleports near an enemy, slashing them. This is a mix of her critical attack and her normal attack as a Lord before she is promoted in Fire Emblem. This attack is amazingly powerful and accurate, even against a moving or airborne foe as well as being capable of hitting Sonic out of his Final Smash. It can also hit enemy that is edge grabbing. Her attack can KO at damages as low as 32%, and can only be avoided with a well timed airdodge or roll. She usually hits the opponent closest to her.
In this appearance, Lyn wields the Mani Katti, not her more powerful quasi-legendary Weapon, the Sol Katti, in comparison the playable Fire Emblem characters (Marth, Roy and Ike), who fight with their legendary weapons (The Falchion, Sword of Seals, and Ragnell, respectively). However, the Mani Katti is the partner blade of Sol Katti, both of which are unique to Lyn.
 Trophy Description
An 18-year-old nomadic girl. Lyn is a strong-willed youth whose skill with the blade draws many admirers. Lyn sets out on her quest to become a master swordsman after coming to the aid of a fallen traveler. She soon learns she's a living member of the nobility of Lycia, a neighboring country. Soon she's involved in a violent dispute over the ascension of the Caelin throne.
Lyn also makes an appearance as a sticker in Brawl.