Marvel has once again proven that they can do just about anything they want. They turned a ragtag band of alien vagabonds including a raccoon and a tree into one of their best movies. They overcame a slow start in Marvel's Agents of S.H.I.E.L.D. to prove that primetime TV is another domain for the Marvel Cinematic Universe to thrive. And now, with Marvel's Daredevil, Marvel has proven that they can (1) conquer the fertile world of Netflix binge-watching shows, (2) overcome a stigma over a character created by a previous, subpar movie, (3) and excel in the darker, gritty world of such characters as Batman.
Now that the 13-episode Season 1 has been consumed by so many, there are bound to be thousands of ideas and theories, from the obvious (yes, the Greek girlfriend with whom it didn't work out was surely Elektra) to the absurd (FOX will not allow a Daredevil/Wolverine crossover).
Allow me to throw my hat in the ring: I have a theory bound to affect the entire MCU, perhaps in Phase 4. Madame Gao, the Chinese heroin druglord in Kingpin's network is, in fact, a Skrull.
(NOTE: For those familiar with the lore of Iron Fist, there is plenty of evidence that Madame Gao is from K'un L'un. I am not presenting an argument against that theory, which is likely. Rather, I present an alternate theory.)
THE PRIMARY EVIDENCE (spoilers)
In the penultimate episode, Madame Gao and Owlsley are discussing recent failures. Daredevil has decimated her heroin production capabilities, and Kingpin is close to discovering that both Gao and Owlsley conspired to assassinate Kingpin's girlfriend. Owlsley has his own plan to thrive and survive (which fails, see the final episode). Madame Gao indicates that her plan is to retreat to her homeland and reflect. To which, Owlsley replies, "To China?" And she replies, "No, a much more considerable distance."
What a peculiar statement! There are a handful of nations further from New York than China, but nowhere on earth is "considerably" farther from New York than China. This would lead one to believe that we are talking about another planet or realm, like Asgard.
Asgard is unlikely, as are the other realms that Asgard oversees. The Thor films, Avengers, and Marvel's Agents of S.H.I.E.L.D. show us that Asgard deals harshly with such cross-realm exploitation. So, we are probably talking about one of the planets in Midgard's (Earth's) realm.
That still gives us as many options as there are characters in Guardians of the Galaxy. Why Skrull?
THE SUPPLEMENTAL EVIDENCE (still spoilers)
Madame Gao says that she doesn't really care about heroin, i.e. she isn't very concerned that Daredevil put her business to a halt. In her line of work, that means that she doesn't really care about profits, which is illogical. Ergo, her drug empire is a massive ploy to ... do what? Spy on Earth, perhaps? Taking the form of a small, elderly immigrant, she ensures that most Americans will overlook her, a tactic she exploits even more so when she employs blind people to run her drugs.
Furthermore, she was able to get to know how the Earth 's criminal underground works, in detail. She was able to study the city where the Chitauri invasion failed, and the Skrulls and Chitauri share an unclear connection (at one time, the Chitauri were the Marvel Ultimate line's Skrulls, but both species have since appeared in the Ultimate titles).
In an earlier episode, Gao was able to determine that Kingpin was hiding his prodigious language skills. Fisk didn't want the Japanese or the Chinese to know he knew their languages, preferring to use Wesley as a translator. (He may have also known Russian.) At the time, I thought nothing of it, except that Gao is particularly observant. Now, I think she recognizes when others are pretending, for that is exactly what she is great at.
Finally, when Daredevil gets close to her, she throws him like a ragdoll. She immediately escapes instead of fighting him. One could interpret this as a martial arts mastery, like the Japanese mobster Nobu. But it makes more sense that she is merely as strong as her species.
If this theory is true, then we may be looking as the seeds for The Secret Wars as the overall plot of Phase 4 and the particular plot of the fifth Avengers movie (since The Infinity War is two movies).
There is precedent for this. Marvel is introducing The Inhumans in Marvel's Agents of S.H.I.E.L.D. We already know that there will be an Inhumans movie, and that they'll figure into The Infinity War. I've actually been surprised how much the Inhumans have factored into Marvel's Agents of S.H.I.E.L.D.'s second season.
If this Madame Gao-Skrull theory is true, I wouldn't expect the concept to be explored too thoroughly on a Netflix series. However, a major hint followed by bigger hints? Entirely plausible. I would expect the major reveal to come in the stinger to Avengers: Infinity War, part 2. Example: an Avenger dies, perhaps Hawkeye. Cut to mid-credits stinger: a doctor discovers in autopsy that ... gasp! ... this isn't Hawkeye! This isn't even a human! Then, Phase 4 movies are overshadowed by a McCarthyism-esque fear, not knowing who is real and who is a Skrull.
That is my theory. What say you?