Thread:BlazingKey/@comment-25296063-20140409001707/@comment-24637501-20140409010612

Honestly I say it isn't worth it unless you have a maxed out team of 5 stars. Cordelica is hard. The farthest I am is... somewhere in the light zone.

But yes You want a gem. Look up on the wiki here for info on the Quest. You want to bring stuff to counter Emilia's Paraylzing attacks. If you have an ally that can Heal like the Tree bring them. Always keep a gem for Cordelica though you have to think hard before you use it. "Do I want to use this gem? for this boss?"

If you die before getting to the boss I recommend giving up that quest for now and trying again Later.