Riviera: The Promised Land

I used Ecthel, Serene, and Fiaa for this one.

For the first half, pummel Ledah with whatever you can throw at him (Serene and her Ice Techs are the best approach, but be sure to keep her healed by Fiaa or you're not going to stand so much a chance). The second half, Ledah is going to hi-resist holy attacks (if you're thinking of pulling Ecthel's Disaresta, that is only meant to be a method of getting an S-Rank finishing blow, so you got to whittle his HP way down). Rely on the hurt-and-heal tactics (if you have the Book of Gelt or Kirie, Fiaa can really heal more than half the HP of your entire party in a cinch).