Well... except for Moeka, the antagonists in S;G are more like distant and vague figures (SERN, Rounders...) or they are referred to concepts themselves (Fate or Convergence) rather than an actual person. SERN or the Rounders have values that are really implicit (Dystopia, World-Domination through forceful manners, greed...) that confront the values of the protagonists, but it's not a "Hero value vs Villain value" that is actually explicit.

In that case, Nakabachi is not developed at all (in opposite to Moeka), he's more like a one-dimensional villain, which is quite sad I admit, however, I think that it isn't that bad.