Is there a way to boost my magic damage?
Celestial Weapons ignore physical but not magical defense, or custom weapons can have the Piercing ability applied to them.
Physical attacks can also get critical damage.
Is there a "Piercing ability" or critical hit for magic attacks?
Best Answer
After looking over this list of weapon and armor abilities, I can conclusively say: No, there is no ability which ignores magic defense.
Conversely there is no physical corollary for Magic Booster which: "Increases potency of magic spells by 50% but doubles their MP cost."
As far as criticals, magic cannot critical: http://www.gamefaqs.com/boards/643146-final-fantasy-x-x-2-hd-remaster/68388299 I wish I had a better source but I can empirically say that I have never seen a magic critical.
(Note that I'm referring to castable magic not thigs like Kimahri's overdrives which can critical.)