Sephiran

Sephiran (JPN: セフェラン, Seferan?), sometimes known under his title of Duke Persis, is the Prime Minister of the Begnion Empire and the seniormost member of the Begnion Senate, first appearing in Fire Emblem: Path of Radiance in the guise of a pilgrim, though he is later shown to stop the Black Knight, though the reason for the knight's obedience is not revealed until later in the second game, Fire Emblem: Radiant Dawn

Past
He was once known as Lehran (エルラン, Eruran?), the thousand year-old heron who accompanied the Goddess in her battle against the dark god, and it was he who imprisoned Yune within the medallion that would one day be known as the Fire Emblem.

Upon marrying Altina, the founder of Begnion, she bore his child, the very first Branded, thereby creating the Apostolic dynasty, every member of which was blessed, as was Lehran himself, with the ability to hear the voice of the Goddess Ashera. Shortly after the birth of his child, Lehran lost the ability to transform and to sing galdr, becoming neither beorc nor laguz.

Following his transformation, Lehran retreated to Goldoa, where he lived secretly under the King Dheginsea's care for seven hundred years. He later departed Goldoa in search of a means by which he might end the mistreatment of laguz slaves due to the extreme isolationism of the dragon kingdom. While in Begnion, Lehran met Misaha, the Apostle who would become the grandmother of the Empress Sanaki, and convinced her to reveal her Brand to the world.

Role in Path of Radiance and Radiant Dawn
He is not revealed as a major antagonist until the end of Radiant Dawn, at which point it becomes apparent that he was the orchestrator of many events transpiring in both Path of Radiance and Radiant Dawn.

Through both games, his final goal, the revival of Ashera for the destruction of the world and the purging of both Beorc and Laguz, is nearly fulfilled as all those not under the protection of Yune are transformed into stone with the outbreak of war across the continent. In his eyes, the Beorc and Laguz cannot change, and will continue along their path of violence and destruction so long as they are allowed.

He is fought by Ike and his chosen companions in the Tower of Guidance in Part IV Endgame IV. Ike figured out that Sephrian has been behind many of the past events as well as being the master of the Black Knight. Sephrian admits all the tragedies he has caused much to Sanaki's dismay and Ike's anger. Ike tells Sephrian that he will make his death as painful as possible. The party is forced to defeat him in order to fight Ashera. During the first playthrough, he has to be killed, but that can differ in subsequent playthroughs.

Additional Playthroughs
In additional playthroughs, Lehran's death can be prevented if certain conditions are met. The conditions involve using the Black Knight in Part I Endgame as well as sparring Pelleas' life towards the end of Part III. It also involves Ike initiating a fight with the Black Knight in Chapter 3-7 and does not kill him. The game needs to have been completed at least once.

Prior to meeting Sephrian in the Tower of Guidance, it is revealed in Ike's own "memory scene" that it was Sephiran who sealed Ike's memories of his mother's death to spare the young boy the pain of living with witnessing Elena's death at the hands of her beloved. This causes Ike's motivation to defeat Sephiran to be alter because he wants more answers about that event rather than just giving Sephrian a painful death.

After Sephiran's defeat another special "memory scene" plays, it is revealed that his decision to awaken the Goddess was largely influenced by the Serenes Massacre, during which all but a few of the heron royals were brutally murdered by Begnion citizens. Before Sephiran dies, Micaiah is able to save his life. Ike convinces him that he should try to make up for his past actions and help them defeat Ashera. He is reluctant at first, but he eventually decides that his actions have been wrong, and he joins as a playable character. When the game ends, Sephiran lies in Serenes Forest by Lorazieh's urging and allows the galdr to heal his worn and ragged soul. It is there where Lehran welcomes the return of Ashunera a thousand years later, and appears with his black wings visible. It is revealed that humanity has been living peacefully for the past thousand years, but tensions are beginning to mount again. However, he believes that another hero similar to Ike will step forward to help put an end to it.

In the final fight with Ashera, he bears only the Ashera Staff, disappointingly forsaking his powerful personal tome, Creiddylad.

Based on the fact that the expanded epilogue involves him a great deal, it can be assumed it is the canon ending.

Trivia

 * In Path of Radiance he is also mentioned as the Duke of Belsys and the Duke of Perseus. This was just a mistake in the translating process.