Lyon was a Queen's Knight apprentice who also served as the bodyguard of the Prince of Falena. As a bodyguard, she takes her duties very seriously but underneath all is a softly spoken, kind hearted young woman.
In her past, she had been taken as a child and raised by Nether Gate. Under the name Mismar, she had almost completed her training to become a full-fledged assassin when Ferid disbanded the group and found the young girl. Ferid was also the one who named her 'Lyon'. As Lyon showed amazing skills with a blade, Ferid allowed her to become a Queen's Knight's apprentice and his son's bodyguard, honours Lyon believed she never deserved. Lyon swore to protect the Prince at all costs, and in doing so, followed him everywhere.
During the Sun Rune War, she encountered Dolph, another member of Nether Gate she formerly knew. Due to Lyon's forsaking of Nether Gate and its ways, Dolph considered her a nemesis. As such, Dolph would use any excuse to attempt to kill Lyon, as was demonstrated when he stabbed her during the New Queen's Campaign. Mortally wounded by Dolph, Lyon laid dying, but thanks to the Dawn Rune her condition became stable, but was far from fully healed.
Desperate to save Lyon, the Prince went to the Sindar ruins in the Deep Twilight Forest in order to find a way to use the Dawn Rune's mysterious power to fully heal Lyon. Having been successful, the Prince returned and used the Dawn Rune on Lyon, allowing her to return to full health. Lyon came into possession of the Twilight Rune shortly before the death of Sialeeds, during the reclamation of Sol-Falena. Lyon used the power of the rune in conjuncture with the Prince's Dawn Rune and together their combined power was able to open the way to the Ashtwal Mountains, in order to pursue Marscal Godwin who had stolen the Sun Rune.
There, Lyon duelled Dolph, who was blocking the way to Marscal, and emerged victorious. However, it took the power of her rune to finally destroy him, allowing the group to progress.
After the war's end, Lyon became a Queen's Knight serving under the Prince, who had become the Commander of the Queen's Knights.
- Gensosuikoden Kiwami Encyclopedia, page 681