WARNING: This article contains spoilers for the first four episodes of Marvel's The Defenders, which arrives Aug. 18 on Netflix.
The Black Sky, the fabled "bringer of shadows" introduced in Daredevil's first season, is an ominous yet nebulous concept, inspiring a murky mix of dread and confusion. However, this ultimate weapon coveted, and possibly worshiped, by the Hand was quickly snuffed out, only to assume a new form in Season 2 as Elektra, who was seemingly destined to serve the ancient order, or maybe lead it. That part wasn't exactly clear. But while Marvel's The Defenders answers some questions about the nature of the Black Sky, it raises more still.
Foreshadowed in Daredevil's debut episode by kanji letters atop a map of Hell's Kitchen, the Black Sky doesn't actually arrive until more than halfway through the season -- first in the somber warning of Matt Murdock's mentor Stick (Scott Glenn), and then, in the flesh, within a shipping container smuggled onto a New York City dock.
The steel doors open to reveal a startling incongruity: The "bringer of shadows," the deadly weapon Stick has pursued halfway around the globe, is a wide-eyed prepubescent boy. Manacled to the container's floor (whether that's to prevent escape or protect his captors is left to the imagination), the sight of the child is intended to surprise the audience and draw a stark contrast between Daredevil (Charlie Cox) and his mentor. One won't permit an innocent boy to be killed, and the other won't allow an existential threat to survive. As we soon learn, Stick ultimately fulfills his mission, off-camera. "I put an arrow in that thing's heart," he tells an indignant Matt.
Beyond a lament by secondary antagonist Nobu Yoshioka that "it will be difficult to locate another Black Sky," as they're "extremely rare," the Hand's ultimate weapon is swiftly forgotten for the remainder of Daredevil's first season. The bringer of shadows seemed little more than a brief, if vaguely apocalyptic, distraction. That is, until Season 2.
With the introduction of Elektra Natchios (Elodie Yung), and her integration into Matt Murdock's backstory, we learn that maybe the Black Sky isn't that rare. Taken in as a child by Stick, who had identified her as a Black Sky, Elektra was trained to become a weapon in the Chaste's centuries-old war against the Hand. However, when another member of the order discovered her true nature, and vowed to kill her (or it, to use his word), Elektra was secreted away to live as the adoptive daughter of an ambassador and his wife. However, a high-priced education, and a life of luxury, didn't divert Elektra from her path because, in the brutal world of Daredevil, there's little escaping who you are. And Elektra was -- is -- an assassin, a living weapon, whether wielded by the Chaste or by the Hand.
Through a circuitous route of complicated relationships, punctuated by betrayal and bloodshed, Elektra ends up tempted by Nobu, who reveals she's the Black Sky, whom the members of the Hand "live and die to serve." Despite being at war with herself all her life, and despite being assured "you are home now," Elektra resists the temptation to take her place with the Hand, and ultimately sacrifices herself to save Matt. However, that's not the end, for either Elektra or the mystery of the Black Sky.
Laid to rest by Matt and Stick, Elektra is dug up at the close of Daredevil's second season by the Hand. By the time The Defenders opens, she's not quite alive (Matt notes she has no heartbeat) and certainly not "well" by anybody's definition. However, she's been out of the grave for some time, exterminating the Chaste and anyone else who might complicate what the Hand has planned for New York City. But whatever the Black Sky is, she isn't "served" by the Hand; she serves the Hand. That's not so suggest she isn't valuable to the ancient order -- she clearly is, as Sigourney Weaver's Alexandra uses the last of her organization's "resources" (presumably, the stockpile of blood from children, and whatever other materials are required for the rite) to resurrect Elektra. The Black Sky is so necessary to the Hand's goals that Alexandra, whose organs are shutting down, is willing to jeopardize her own long life.