Seikon-Shoukougun is correct with ????. However, try to limit yourself to one guess per post in the future. From this point on, I'll only count initial guesses.
The explanation is as follows.
Each stanza addresses an enemy that can use ????. Only two such enemies, Jersey and Behemoth, exist.
Quote:
I am a peculiar kind of justice
A reference to both the Jersey enemy and the fact that there is a kind of literal justice to ????--it deals the same amount of damage the caster has suffered.
Quote:
Although some might see me as nothing more than Revenge
In FFVI, ???? was called Revenge.
Quote:
Old Testament, even; fairness in punishment,
A reference to an idea that recurs throughout the Pentateuch; "an eye for an eye." This literally applies here, as the caster inflicts damage equal to that endured.
Quote:
And just as contemptuous of magic.
"Magic" is frowned upon in the Bible. The Jersey enemy (to which this stanza is applied) can switch between physical immunity and magical immunity. ???? is only used when Jersey is immune to magic.
The second stanza revolves around the Behemoth enemy.
Quote:
I am a peculiar kind of justice
The equal damage idea seen before.
Quote:
Fit only for commons, unworthy of a King
Only "common" Behemoths use ????. King Behemoths do not have this ability.
Quote:
The kind applied roughly in dark alleys
A reference to Midgar, where Behemoths are encountered.
Quote:
With malicious intent, and more force than before.
Given that a Behemoth has more HP than a Jersey, the potential damage of ???? is much higher (hence, "more force").
Anyway, you're up Seikon.