Idenn (translated Idoun, or Idun in fan translation), 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 Fae. 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 and disappeared, Idenn stayed behind because she feared the Divine Dragons would go into conflict with the others and was captured. She was then made into the Demon Dragon, but she would not follow the commands given to her, so the dragons destroyed her soul in order to gain control over her.
About a millenium after her defeat, she is unsealed by Zephiel, Hartmut's descendant and current King of Bern, and serves him as a vital part in his scheme to bring new order to the world. If the player collects all the Legendary Weapons, Roy will go out, after defeating Zephiel, to find Idenn. Despite Roy's pleas and insistence that she should not follow the now deceased Zephiel's commands, she refuses to submit and transforms into her dragon form to attack his army.
In the best ending, she again survives and is taken to Arcadia; she is seen laughing and playing with Fae, finally showing signs of recovering her soul. If the player fails to get all the Legendary Weapons, the game ends after defeating Zephiel, and Idenn will disappear
|Mage Dragon |None |20 |78 |29 |23 |16 |18 |30 |21 |25 |2 |Breath |Dark Breath
Idenn is quite brave to have taken on the eight legendary heroes (even though she lost). She serves Zephiel selfesly (probably because he broke the seal on her) but then one must remember her soul was destroyed so maybe it means that she could not tell right from wrong back then. She seems dark and somewhat lonely.
Remember what Max in the Get Smart movie said as this would imply very well to Idenn.
In the best ending (the one involving Fae) she is relearning what things are (such as Fae teaching her what a tree is) and when Fae hits the tree and an apple falls on her head Idenn laughs showing the first sign that her soul is recovering.
thumb|300px|right|Idenn's main theme: Dark Priestess thumb|300px|right|Idenn's battle theme: Shaman in the Dark Idenn's event theme is called Dark Priestess and plays in events where she is the focus. Her battle theme is called Shaman in the Dark.
- In cutscenes she appears as a female Shaman, similar to Sophia.
- Like Ranulf, Idenn is a Heterochromic (although it is more noticeable when she is not wearing her hood): her left eye is green and her right eye is violet sort of colour (same colour of Fae's hair)
Idun is the Norse goddess of eternal youth, who guards the golden apples of immortality which keep the gods young. In one myth, a giant named Thiazi captured Loki, the Norse trickster god, and only released him on the condition that Loki help him steal Idun's golden apples. Loki obliged, luring Idun away by saying he had found more apples like her magical ones. When the gods began to age and die without Idun to guard their youth, they forced Loki to rescue her again. He disguised himself as an eagle, flew to Thiazi's palace, and there transformed Idun into a nut and carried her back to Asgard, the gods' kingdom. Thiazi pursued but burned his wings on the fires the gods set against him, fell to the ground, and died. Idun was returned to her original form in Asgard.
The name Idun comes from early Norse elements 'ið' meaning 'again' and 'unna' meaning 'to love.'