this fight is really hard for the average joe (me)
you don't really NEED to cancel every omen but it makes your life easier. I failed to break the 10m skill dmg one by a few hundreds and this ended up being a pain in the ass, but we survived somehow
the requirement of needing a field effect makes things hard for earth. You will need to run a MC class with a field effect (Masquerade, Rising Force, Chaos Ruler or Nighthound), and none of these classes are especially good at this fight.
Since you also need to do an overchain, i decided to go with RF, because you can't depend on Cidala's CA reactivation (lots of dispells and twice a turn as well).
Cidala is also a good choice here because she brings lots of debuffs (needed for the 12 debuffs omen. They say 10 but you need to END the turn with 10, and she removes 2, so you need 12). You might need some external debuff sources like summons (I'm using Yukata Freyr here).
10% and 3% are ParaLost-esque raid wipes (18-hit 100k static). I guess you could cheese it with a really high damage reduction to get it to tankable levels, but its easier to have a sub-all character like Naru or Cidala to tank it for you.
I think Dark is the element that will have the easiest time doing it, as its regular team (Fediel+Lich) can cancel half the omens by themselves. I might try to do it in Dark later today if I recover from the ~2 hours i wasted changing my earth team to actually beat her.
I mean haha me too thanks