This just occurred to me. I need to level/evolve five Merith to two-star, level them up completely, and then find a five-star Aem. The Frontier Hunter is only around for a few more days, and I need this team to so I can obtain that Medulla Gem. I have three Merith now, as well as the materials to evolve them, I just need the XP. Capturing two more Merith shouldn't be that difficult, she seems to drop pretty much all of the time [Egor Snowfield, second stage].
The strategy is:
When you reach Juggernaut in Frontier Hunter, heal the first turn, then guard the second/third. On the fourth heal again, and then guard on the fifth [he'll use his Brave Burst dealing a lot of damage]. Afterwards, rinse/repeat until you get the 850,000+ points needed for the Medulla Gem.
This is only possible with Aem as your Friend, since it allows your BB Gauge to build without attacking [so you can heal]. It's effectively a "tank strategy", and will take a while to accomplish [around 4+ hours]. Even still, the Rewards for doing so are worth it apparently, since the Medulla Gem is arguably the best Sphere in the game right now [+20% to all stats].
I just hope I can get enough XP to accomplish this. ~_~