The map you will be playing at.
Aquanos can be a frustrating map at some times, and this is why I've created a guide for it. I just got Aquanos today, but I've completed it three times already flawless. Aquanos is a frustrating map because of the sharken. The sharken are creatures that essentially push your defenses out of the way to get to the eternia crystal. Their damage isn't anything to ignore, which makes them even more of a priority. I recommend that you should have all characters above 70, but it's okay if you don't, you'll just have to do more work. I have a setup that is in this link [1]. It should help, and It does work every well. I recommend that you do this with two people or maybe even three, but it is possible to solo. If you solo, it will require ALOT of work and constant repairing.