It always seems like they develop the mysterious-to-the-point-of-antagonistic character when the main character is in greatest despair. They did this in Madoka, too. Why do they do this?
I really misread Saya. I had assumed she was another archetypal evil manipulator, but she, like Homura, was probably the true protagonist, locking away her own feelings in order to do whatever it took to protect another girl, even if it meant acting the antagonist.
Really, though, I should have expected it. In a world where everybody fights, the two that were doing the least fighting were Black Gold Saw and Strength. Black Gold Saw constantly watched over the others and her puppets while Strength acted as the undertaker for the fallen. The two could easily be interpreted as guardians.
Our predisposition to Black Rock Shooter being the protagonist fooled us. Things aren’t as simple as they seemed.