How do you unlock Sephiran in Fire Emblem?

Answer 1

First off, you need to be playing at least on your second play-through. After completing the game for the first time, you need to start from the beginning. There are two things you need to do specifically.

1: Use the Black Knight on Part 1 Endgame.

2: Have Ike talk to the Black Knight on the chapter: Rivals Collide (which will be in Part 3).

This last part is almost impossible considering that the Black Knight is between 20 to 30 levels higher than Ike so you will need to be creative on how you fight him (Here is some advise, 1: lure the black knight to an isolate position. 2:Have Ike withing attack range by turn 12. 3: Have a strong support bond with someone nearby. 4: Battle save before pressing "End". 5: repeat until Ike miraculously avoids a blow.)

If you do all this, then rather than letting Sephiran die in part 4, Yune will save him at the very last moment. This will allow you to use him in the final boss battle and then unlock a secret ending.

Answer 2

SPOILER!

He is only unlockable in the second playthrough.

You must use the Black Knight in the endgame of part 1 and you must spare Pelleas' life.

You must also have the Black Knight get attacked by Ike in 3-7 and have both of them live.

You will get an altered memory scene for Ike and he will decide to spare Sephiran's life instead of ripping him to shreds.

how can i keep both Ike and black knight alive wenn Ike have to kill the black knight?

Answer 3

on Part 3, the chapter with the river crossing with the Greil Mercenaries, get Ike to fight the Black Knight. Don't let anybody die and in the Endgame, you can get Sephiran. Ike needs at least 27 speed. My way is to attack the Black Knight, then rescue him with Haar.