But Mariah did not become the arch-villain. At least not this season.
It's a little over halfway through the season before we even meet Diamondback. Plenty of time to spend trying to suss out who, exactly, is supposed to be our biggest bad.
And the reveal of Willis Stryker was, I felt, ultimately disappointing.
I liked Diamondback as a villain in many ways. He was cold-blooded, somewhat unpredictable, and Erik LaRay Harveyo sold me on that. I liked the scene where he kills all but one of the crime bosses that Mariah had called to meet.
But as Luke Cage's arch-nemesis, I was less than impressed. I was not sold on their emotional connection. At all. The line where Luke says that the two of them were "like brothers" and Diamondback retorts, "I am your brother," was a good line. But I didn't have emotional connection to what they were saying. I like the flashback scene when young Carl makes a comment about being a “Lucas”, and only we see the expression on Willis’ face. But overall, I never felt any particular affection between them, in the present or in the past.
I wasn’t sold on Willis’ desire for revenge, either. Sure, I get the resentment. Carl got all these goods things he didn’t – and a few more that Willis probably just imagined. But that wasn’t Carl’s fault, and if they really were so close as kids, if Willis knew even at that they were brothers…what changed his mind? Why did he go from friend to implacable foe? Because he went to jail? That was hardly Carl's fault.
Now certainly, there are great stories out there about illegitimate children who turn on their legitimate siblings out of envy. I think Shakespeare may have done a thing or two with that. For me, the first story that comes to mind that uses this plot is the Chosen Two: Buffy and Faith from Buffy the Vampire Slayer. Not technically sisters, not technically illegitimate (well, Faith might have been…but you know what I mean). Still, it’s thematically similar: They are sister-slayers. One has everything (or seems to), one has nothing. But there is a lot of build-up to Faith blaming Buffy for this, and unlike with Stryker and Cage, we see the love between them (even though they were never as close as we are told Willis and Carl were). It's more complicated than just Faith blaming Buffy for her problems. The intense competitive streak between them is part of what drives Faith over the edge, and a major factor in why she turns on Buffy. We also see how Buffy’s well-intentioned condescension makes Faith feel inferior. But Faith is afraid, not just that Buffy is a better slayer, or happier, or luckier – but that Buffy is (morally speaking) a better person. And so she makes it true.
This is far more complex psychologically than Diamondback being mad that Luke was legitimate and apparently had their father's favor he wasn't, and didn't. Why did Stryker decide to blame Luke, instead of any number of other people and factors? It can’t be enough that he suffered while Luke didn’t. Not all illegitimate children, whether literal or metaphorical, blame their legitimate siblings for their problems. To simply take that as sufficient explanation for Willis’ behavior is too…well, comic booky. And it does not help in selling me on the boyhood bond between the two men. As I noted above, there is no sense as to how he got from their childhood closeness to the unrelenting hostility we see in adult Diamondback.
There's another problem with Diamondback as Luke's arch-rival. Putting aside the family connection for the moment, why is Willis Stryker, as opposed to some other villain, Luke Cage's arch-enemy? In the Jessica Jones TV show, the Purple Man is contrasted to Jessica by his callousness: while Jessica cares about people, even those she doesn’t know (“My greatest weakness? Occasionally, I give a damn”), the Purple Man completely disregards the wellbeing of others. Jessica is angry about the lives the Purple Man has ruined, but he considers a nice meal for himself more valuable than anyone else’s life. Matt Murdock and Wilson Fisk are archenemies because they both have a propriety view of Hell’s Kitchen. They both consider the Kitchen "their" city. In the comics, Bullseye’s sadistic chaos is a contrast to Daredevil’s righteous self-control. Peter Parker and the Green Goblin have a personal connection through Harry, but in addition, both have brilliant scientific minds. So does Spider-Man’s secondary arch-nemesis, Doctor Octopus. Magneto and Charles Xavier, in addition to being old friends, are leaders and spokesmen for different methods of furthering the welfare of mutants.
Most of Buffy Summer's seasonal enemies are thematically appropriate to her: The Master is an old patriarch who lives in a world of rituals while Buffy is a rebellious young female slayer who "flunked the written". Angel(us) is the Bad Boyfriend, who turns evil after sex with our heroine, but in keeping with the feminist themes of the series will be defeated by Buffy herself. Faith has Buffy's power-set and calling, the only other one in the world, but she goes over to the dark side. Glory, like Buffy, is a girly-girl you might underestimate until she kills you. Warren's a garden-variety misogynist with too much power.
On Angel, a vampire with a soul working outside the law to do good faces off a law firm of humans who choose to be evil. Over on Supernatural, the Yellow-Eyed Demon is the dark, mysterious power that came into a ordinary family's lives and changed them forever. But the scariest part is that this same darkness is nestled within their family, in their younger son. I have problems with how the Dean-Michael Sam-Lucifer metaphor was handled in s5, but at least it was there.
By contrast, how is Diamondback a contrast to Luke? How are his goals, power set, and personality connected to Luke’s? How does Diamondback help illuminate who Luke is? Aside from a poorly-written family connection, why is he Luke's arch-enemy?