"But Matt, we haven't even got to season 2 yet!"
Yes, I know. Daredevil vs. The Punisher is still on its way, but that doesn't mean a man can't speculate. Daredevil's first season introduced us to a darker, more violent side of the Marvel Cinematic Universe, and season 2 seems primed to do the same, with the introduction of one of the House of Ideas' most infamous killers. Assuming the fantastic series will be renewed for a third season, how can you possibly top Wilson Fisk and the Punisher?
The title says it all. Drugs, death, and the devil. Kevin Smith's Guardian Devil is one of the best Daredevil stories ever written, and is ripe for a Netflix adaptation. The pieces are all in place: Karen Page and Foggy Nelson, Matt's mother, Maggie, could be introduced easily, and Black Widow herself could even make an appearance. Bullseye is set to be introduced in season 2, so that leaves only one character left - the man pulling the strings.
Mysterio is considered by many to be a bit cheesy, especially with his colorful costume and overdone acting (not to mention the fishbowl helmet). But there's more to Mysterio than being a punching bag for Spider-Man. As shown in the Guardian Devil comic, he's got a superiority complex a mile high, a violent streak comparably long, and a fascination with drugs and their mind-altering properties. Sound like someone you might know?
Enter Bryan Cranston, known mainly for his role as teacher-turned-meth-cook Walter White. White has more than enough in common with Mysterio to make Cranston the perfect choice. He's got no issues with violence, he's barely (debatably) hanging on to sanity, and he's even got a stage name/alternate personality in Heisenberg. Both are cancer patients, and on top of that, White's grizzled face bears an uncanny resemblance to the master of illusion.
Those who've read Guardian Devil know it's definitely dark enough to fit the tone of the Netflix adaptations. Given that Kevin Smith also wrote it, Marvel may even be able to hire him to co-direct/advise on the production, to ensure it's faithful to both the comic and the Marvel Cinematic Universe. Guardian Devil, if done right, could top the first two seasons of Daredevil, and even most of the movies in the MCU. Let's keep our fingers crossed.