Stan Lee and Bill Everett introduced Daredevil to the Marvel Universe, but it was in Frank Miller's 30-issue long run on the hero's eponymous comic where Daredevil came into his own.
It's not an exaggeration to say that Miller created a whole new mythos for Daredevil, one which almost all later spins on the Man Without Fear takes their primary inspiration from. This list will count down Miller's ten most significant contributions to Daredevil.
10 Misery, Misery, Misery
Frank Miller's run resulted in an unofficial edict for Daredevil writers that "Matt Murdock must suffer." Over the course of Miller's initial run, Matt experiences the painful losses of both his first love and his mentor. Miller's seven-issue return to the series, for an arc now known as "Born Again," kicked this into overdrive.
After the Kingpin learns Daredevil's secret identity, he destroys Matt's entire life, causing him to lose his money, his apartment, his law license, and very nearly both his sanity and life. Future Daredevil runs, with the noted exception of Mark Waid's, have followed suit. Matt's relationships continually end in tragedy and his identity was made public in Brian Michael Bendis' arc "Out."
9 Catholicism
Miller didn't introduce Matt being a practicing Catholic himself, but he made it an integral part of the character's identity. Reasoning that "only a Catholic could be an attorney and a vigilante at the same time," Miller remade Matt's Catholicism from a background detail into a core part of the character's identity, most notably through the Christian-infused symbolism throughout "Born Again."
Later storylines, such as Kevin Smith's "Guardian Devil," took this even further, while Catholicism was also a crucial part of the characterization of Charlie Cox's portrayal of Matt in the Netflix Daredevil series, which examined the irony that a man of God dresses like the Devil.
8 Rivalry With The Punisher
By the time Miller got his hands on the character, The Punisher hadn't reached the apex of his popularity, but Frank Castle's guest appearances in Daredevil #181-184 played a key role in making him more than a minor Spider-Man adversary. Carrying on from Castle's arrest in The Amazing Spider-Man Annual #15, Miller introduces the Punisher imprisoned on Ryker's Island, but he's soon freed by a federal agent who points Castle in the direction of a drug exchange the agent himself is barred from interfering with.
From there, Castle resumes his war on crime, coming into conflict with Daredevil over their differing views on lethal action against the criminals they both fight. This sparked the beginning of a long-running rivalry between the two, both on the pages of comics and in the realm of television.
7 Noir
Miller had wanted to write crime comics, and when he took over the writing duties for Daredevil, he gave the comic the tone of a film noir. His art made more stylistic use of shadows than previous issues had, while writing-wise, the comics' narration went from typical exposition/recap to a hard-edged internal monologue right out of a Dashiell Hammett novel.
Fittingly, Miller's debut issue, #168, employed one of the most common stories in noir; the hero's lost love returning to them but as an adversary.
6 Grit
Before Miller, Daredevil's comic adventures had the standard tone of a superhero story, being outlandish, whimsical, and weightless, with Daredevil fighting primarily C-List super-villains who looked like rejected additions to Spider-Man's rogues gallery.
When Miller took over, this approach was jettisoned. As part of his noir-tinged reinvention of the Man Without Fear, Daredevil stopped facing down supervillains and instead fought mostly ordinary criminals and gangsters, often pumping the patrons of Josie's bar for info. This made Daredevil stand out all the more next to his peers in the Marvel superhero pantheon, and most subsequent runs have continually steered Daredevil away from world-ending threats to more grounded villains.
5 The Hand
The threats faced by Miller's Daredevil weren't all the realistic side of things, however; one of Miller's most significant new additions to the Daredevil mythos was evil ninja clan The Hand.
Miller kept the Hand as mostly a background threat relative to the menace of organized crime, and both their origins and very nature remained enigmatic. Still, the Hand became an increasingly important part of the Marvel universe after Miller's run ended, to the point that a loosely-adapted version of the group was used as the main antagonist for The Defenders.
4 Stick
In Daredevil #176, after losing his radar sense in an explosion, Matt seeks out the man who trained him to hone those senses, a blind man by the name of "Stick." Stick agrees to help his old student regain his senses; their training is chronicled in the subsequent issue, #177.
Afterward, Stick was revealed as a member of the Chaste, the Hand's eternal enemies, and Elektra's sensei as well, something that was imported in Scott Glenn's portrayal of Stick in the Netflix Daredevil series.
3 Made Bullseye A Serious Threat
Bullseye, created by Marv Wolfman, debuted in Daredevil issue #131, but his gimmick-laden costume and persona mean he almost certainly would've ended up a D-Lister forgotten by history had Miller not come along. Across Miller's run, Bullseye enacts multiple (failed) revenge schemes against Daredevil, is employed as the Kingpin's chief assassin, murders Matt's first love Elektra and earns himself a paralysis as a result.
The bed-ridden Bullseye is the co-star of Miller's final issue, "Roulette," where Daredevil concludes the pair are stuck together. This run of events elevated Bullseye into Daredevil's second-greatest enemy, and later writers have taken their feud to further depths.
2 Made Kingpin Daredevil's Archenemy
Miller poached more than a few Spider-Man characters for Daredevil, but the most significant addition was Wilson Fisk, aka the Kingpin. After previously being a recurring adversary of the Wall-Crawler, Miller brought Fisk out of retirement literally and metaphorically, having him resume control of New York's crime syndicates and become the overarching villain of the series.
"Born Again," where Fisk systematically destroys Matt's life, cemented the Kingpin as Daredevil's arch-enemy, and ensured that he's remembered more as a Daredevil villain than a Spider-Man one. That's reflected by him being the main antagonist of both the Daredevil film and television series.
1 Elektra
Miller's greatest addition to Daredevil remains Elektra Natchios, for she was solely Miller's creation. Her debut issue, #168, reveals that during college, she and Matt Murdock had been in love, but fallen out after the death of her father. Seeking an outlet for her rage, Elektra trained in martial arts and became an assassin, eventually being hired by the Kingpin to kill the man she once loved.
Felled by Bullseye with her own sai in issue #181, Elektra was resurrected by The Hand in issue #190, but Matt's love for her ensured the Ninja cult's attempts to infuse her with their evil failed. Miller had intended that as the final end to their star-crossed love, but later writers couldn't resist bringing Elektra back into Daredevil's life.