Lethe is a character in the Tellius Fire Emblem titles, Path of Radiance and Radiant Dawn. She is a member of the beast tribe of the laguz. and a servant of Caineghis, the king of Gallia. Like other members of her tribe, her humanoid form features feline traits such as ears and a tail, and she has the power to transform into a large cat. She is also a friend and partner of her fellow beast laguz Mordecai, but unlike her large, gentle companion, Lethe is short-tempered and holds a great deal of contempt toward beorc.
Lethe is one of the first laguz that the Greil Mercenaries encounter in Fire Emblem: Path of Radiance. She and Mordecai are assigned by Caineghis to accompany Elincia and the Greil Mercenaries on their journey to Begnion, Though Lethe detests the idea, she follows her king's orders while still harboring her hatred of all things beorc. However, as the game progresses and she fights alongside Ike and other beorc in the war against King Ashnard, she reassesses her condescending views and becomes more friendly towards her comrades.
Following the death of King Ashnard, Lethe returns home to Gallia. However, during the events of Fire Emblem: Raidant Dawn three years later, she once again joins the fight, this time as a warrior of the Laguz Alliance in their war with Begnion. She plays a significant role in the chapter "A Reason to Fight", in which she leads the Gallian Army against the player-controlled Dawn Brigade.
Lethe has a twin sister named Lyre. Unlike her sister, Lyre is in general more friendly and playful, and the contrast in the sisters' personalities leads to frequent quarrels. Despite this, Lethe goes to extreme measures to protect her.