Lightning: Requiem of the Goddess

The challenging aspect regards really just going through the effort, time, and learning process that it takes to use her, defeat Caius twice (two forms and needs to be 5-stars for both), and then finally have her at the end of the extra story. I don't recommend playing it until you've completed the main game, as there are indeed spoilers in this extra story. If you have? Awesome! Definitely recommend. She's powerful as a party member, and it's really fun watching her destroy. :)

Boring bull where lightning bashes her head on the wall until she breaks through. Watch it on youtube and don't give these clowns a dime.