I still don't understand Diamondback's part of the story. It just doesn't make any sense.
He hates his half-brother despite being his best friend, and for some inexplicable reason, spontaneously puts all of his hatred towards his father into him after they get arrested. That, alone, is pretty 'eh?' but then it just gets dumber and dumber. Next, he waits until his brother gets out of the Marines and becomes a cop, then somehow frames him for something bad enough to get him sent to a hardcore prison with zero protection due to being a cop (and in fact, having guards and psychiatrists proudly proclaiming it for everyone to hear; sure, that could be reasoned to be part of their goal to find suitable test subjects, but it never raises a brow in anyone at all, including Cage).
Then, apparently, while Cage is in prison, Diamondback decides to move to Harlem and start taking over the criminal underworld there. (Remember; he was already hardcore enough that Cottonmouth himself was scared of him before Cage even got his powers.) Because, uh, somehow he knows his brother is going to wind up there with superpowers, as it's all part of his master plan to take him out? Even though Cage has never been to Harlem, didn't even go to Harlem to begin with, and was presumed dead at the prison, but still Diamondback knew this was all part of his master plan.
And then... it just... I don't even.... Seriously, wtf? This character makes no god damned sense from top to bottom.