When you first hear the name Buffy the Vampire Slayer, you might be left with the impression that the series itself revolved around its titular character, a former cheerleader-turned-slayer of evil and thwarter of multiple apocalypses — and you'd be partly right. When the show first debuted on the WB back in 1997, its lead, Buffy Summers (played with cheerfully witty aplomb by Sarah Michelle Gellar) was our in to a world of vampires and vengeance demons, body-swapping witches and bitchy popular girls. But, as she soon discovered, she didn't have to face them all alone.
Enter the Scooby Gang, initially consisting of Buffy's new friends introduced in the first season — wisecracking skateboarder Xander Harris (Nicholas Brendon) and shy, book-smart, socially awkward Willow Rosenberg (Alyson Hannigan). After finding out Buffy's secret — that she was a Slayer, one chosen out of every generation to stop the forces of darkness — they became a permanent fixture in her lives, not just as members of the Slayer's inner circle but as her support system too. Buffy may have been our gateway, but as the show progressed throughout its seven seasons — first on the WB and then shifting to UPN for the final two — we got to know her friends too, and the series became just as intimately about their growth and their respective journeys. In fact, if there's one character who arguably developed as much strength and power as Buffy did from series' beginning to end, it's Willow.
Out of the rest of the Scooby Gang — which later expanded in the early seasons to include other members like queen bee Cordelia Chase (Charisma Carpenter) and cool guitarist Oz (Seth Green), who would become Willow's boyfriend throughout her later high school years and into college — Willow consistently demonstrated the most natural proficiency at a number of different skills. If something needed to be found via the Internet — back then a nigh-Herculean task when Being Online was such a newfangled notion that it was even written in as a Season 2 point of contention between Buffy's Watcher Giles (Anthony Stewart Head) and new computer teacher and self-professed "technopagan" Jenny Calendar (Robia LaMorte) — Willow was always the one the group relied on for a necessary bit of hacking. Her eventual leap from technology to magic might have been an unexpected one, but in the realm of Buffy, it only recentered her as an integral member of the team.
But Willow's character evolution wasn't without its ups and downs either; her initial use of a spell to restore cursed vampire Angel's (David Boreanaz) soul to his body started her down a path of both incredible power and devastating consequences. As her aptitude with magic grew, so too did her confidence — and in some cases, her arrogance. She didn't always heed warnings about the potentially negative outcomes of performing certain spells, not necessarily for only herself but for others that her magic could affect. Before their eventual breakup, Oz tried to point out that Willow's dependency on magic was becoming too great, but also made sure to reiterate at every turn that he was only doing so out of concern for her well-being.
In retrospect, Willow's magic arc was often used as an insert for the show to address other issues — her embracing her sexuality, her struggles with addiction, her grief-fueled drive to avenge a fallen lover — and revisiting Buffy now reinforces the fact that it makes for a sloppy metaphor upon later viewings. It's confusing, too, that her powers seemed to represent so many different things over the course of the series — some times positive growth, other times regression into patterns of negative behavior — but rewatching the show makes it more than evident that Willow evolved well beyond the role of supporting character. She might have had her own battles to fight, her own unique demons to overcome, but she did eventually come out the other side of it stronger than she had been before.
At the very end of the series, our Scooby Gang is seemingly on its last legs against the First Evil, the greatest enemy it's ever had to fight, hopelessly outnumbered. Buffy has her friends at her side, as well as a small army of Potentials — girls who haven't been chosen to be Slayers yet and therefore don't have the strength that she does. Of course, that's where Willow comes in; at the climax of the final battle, she performs her most powerful spell yet, one that manages to simultaneously activate every single Potential Slayer around the world, giving them the ability to fight and take down the First Evil and the race of ancient vampires known as the Turok-Han that served in its name, as well as completely bury the Hellmouth that had existed in the town of Sunnydale for hundreds of years.
The further we get from Buffy the Vampire Slayer, the easier it is to recognize it for what it achieved with the female characters it gave us, as well as the ways in which it undoubtedly stumbled in terms of depicting representation and other issues on television, not to mention the tropes it spawned with its questionable treatment of said characters. (The debate over which of Buffy's boyfriends was best will probably rage on for the foreseeable future, though.)
But hopefully, one thing we can all agree on is the fact that Willow Rosenberg was always more than just a "sidekick" for Buffy Summers; she had her flaws, and she definitely wasn't perfect, but looking back on her arc across those seven seasons, she grew far beyond the timid, geeky girl into a confident and powerful witch, and the impact she had on the show can't be understated.