Keine is a special character...how so? The truth of the matter, if used correctly, ANY of her skills can be super deadly. Since Keine is this game's equivalent of Final Fantasy Tactics' Arithmetician/Calculator, you can see why. The above move, for instance, deals damage to all enemies equal to Keine's EXP/500. Now that doesn't seem much early on, but think of it late-game....yeah. And it only costs 18 MP at that! However, keep in mind that Keine's skills DO suffer from Master Spark syndrome, in that they all have lower accuracy (80% accuracy is the norm for basically ALL of her skills), AND in order to get Keine's skills, you have to either win them (which they usually are 3% or less drops), steal them (same deal here, but this is even rarer), or find them (this is the rarest).
For more introspect as to what Keine's skills do? Let's look shall we!
First Pyramid: Damage = Keine's EXP / 500 (MP Cost = 18)
Ephemerality 137: Damage = Target's Defense * 5 (MP Cost = 32)
Buretsu Crisis: Damage = # of times Escaped / 3 (MP Cost = 16)
Masakado Crisis: Damage = # of battles fought / 3 (MP Cost = 30)
Yoshimitsu Crisis: Damage = Target's Attack * 5 (MP Cost = 36)
Phantasmal Emperor: Damage = Damage = (Keine's Attack + Keine's Magic) * 3 (MP Cost = 40)
Legend of Gensokyo: Damage = (Keine's Magic - Target's Defense) * 5 (MP Cost = 40)
Gods' Realm: HP Restored = Target's Level * 50 (MP Cost = 40)
Emperor of the East: Damage = Damage = Keine's Attack + Keine's Defense + Keine's Magic + Keine's Speed (MP Cost = 60)
Rain in Showa: More statuses are healed the higher Keine's Level is. (MP Cost = 26)
Amaterasu: Damage = Target's Attack + Target's Defense + Target's Magic + Target's Speed (MP Cost = 60)
Mito no Mitsukuni: If Keine's HP < or = 10, Damage = 9999, Else Damage = 1 (MP Cost = 10)
Yamato Kingdom: Damage = 100% Target's HP. If HP > 9999, Damage = 9999 (MP Cost = 75)
And that's all of her skills! Whether or not the formulas work or not is another question (they do flat damage, so there's no variance to them except if the stats themselves are increased/decreased inside/outside of battle. And for those of you who recognize it, yes Yamato Kingdom it totally from GoS (it was one of Lithos' attacks from that game). Notice too, that it doesn't have an accuracy modifier on it either. It WILL hit 100% of the time....but this is also assuming you manage to find the darn thing too in the first place.
Keep in mind, if any of these formulas NEED to be changed or HAVE to be changed, I have to copy/paste them into EACH and EVERY monster group in the game....which amounts to copying one page roughly 300-400 times. Yeah, wouldn't be so bad if I could do the formulas in a common event, but alas can't do monster stats in common events ;_;