Idunn

Idoun, the Demon Dragon, is the final Boss of Fire Emblem:Fūin no Tsurugi. Several centuries ago, in the Scouring, she squared off with the Legendary Heroes and lost. But she did not die; the Hero Hartmut, using the Sword of Seals, sealed her away in pity.She was once a Divine Dragon like Fa. When their side was losing due to the fact that humans were more numerous, the dragons appealed to the Divine Dragons to increase their forces with artificially spawned "war dragons." When the Divine Dragons would not comply, Idoun was captured and her soul was destroyed turning her into the Demon Dragon. Now she's unsealed and serves Zephiel, to bring new order to the world.

If the player collects all the Legendary weapons, Roy will go out, after defeating Zephiel, to find Idoun. She will be the last boss of the game, transforming to her dragon form and fighting the army.

In the best ending, she again survives and is taken to Arcadia; she is seen laughing and playing with Fa, finally learning how to have feelings. If the player fails to get all the Legendary Weapons, the game ends after defeating Zephiel, and Idoun will disappear