Iron Man, Rocket the Racoon, Yelena Belova, Loki, Okoye: the Marvel Cinematic Universe has always brought its characters to life in spectacular fashion, and one of the most evolved side characters was also one of the first: the honor belongs to none other than Doctor Darcy Lewis (Kat Dennings). Marvel's Midas touch is especially impressive considering how these household names were originally B-, C-, or even D-tier superheroes in the comics world.

Take Taika Waititi's illustriously chatty Korg, as much of a comic book side character as a side character can be before his onscreen counterpart charmed his rocky way into audiences' hearts. Darcy is no different in that overall regard, but her organic growth from a bit part created for the screen to an active participant in the MCU mythos does exactly what supporting characters are designed to do: fill out the world and add emotional depth.

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Darcy's MCU Origins as a New Character

Darcy (Doctor Lewis if you're nasty, put some respect on her name) was a character invented for the first Thor film, which was only the third MCU entry and the first not headlined by Robert Downey Jr.'s Tony Stark; therefore, it was Marvel's first risk as a budding franchise. With Shakespearian veteran Kenneth Branagh in the director's chair and a sharp, smart, humanist (or Asgardian-ist) script from Ashley Edward Miller, Zack Stentz, and Don Payne, the gamble paid off. Nowadays, it's odd to think of Chris Hemsworth's Thor as an unknown, but this was the MCU's infancy – and the God of Thunder needed a superb supporting cast.

A political science student earning only six credits for her internship, Darcy completes Thor's Earth-based trio alongside Jane Foster (Natalie Portman) and Erik Selvig (Stellan Skarsgård). Marvel is known (and sometimes critiqued) for its constantly witty characters, but in 2011, Darcy was a proto-MCU snarkster. Her tone's as dry as the New Mexico desert; cue the opening scene when she tries to drive away from the Bifrost storm, exclaiming, "I am not dying for six college credits." Or her now iconic ogling of Thor's looks: "For a crazy homeless guy, he's pretty cut." Dennings' deliberate pause between "he's" and "pretty" deserves an Oscar, as does her easy rolling droll of "This is going on Facebook, smile."

Although she infuses every scene with delight, it's easy to dismiss Darcy as little more than a quirky, reckless college kid. But she's the one to realize Thor truly did travel the Bifrost, a deduction responsible for reuniting Jane and Thor after their initial meet cute. That's an inciting event with momentous consequences (everyone say thank you, Taika Waititi, for the Mighty Thor). Beyond her comedic sidekick requirements, Darcy's cleverness and open-mindedness are evidenced by her serving as a middle ground between Jane's willingness to take Thor at his Norse mythology word and Erik's belief in irrefutable science. She's also handy with technology, and her impulsive nature isn't a bad thing -- let's be honest, tasering Thor was smart given their limited information. And much like Thor allows Jane's brilliantly scientific mind to shine regardless of her gender, by no means is Darcy a stereotypical woman. This kind of oddball role would usually go to a man. Quirky, nerdy women exist in droves in real life, so Darcy is mildly revolutionary.

Darcy Stays the Same in 'Thor: The Dark World,' For Better & Worse

Thor: The Dark World sees Darcy still in easy contact with Jane, interrupting her already awkward date without shame and joining her investigations in London. She and Jane are on a more equal professional footing, especially since Darcy hires an intern of her own, Ian (Jonathan Howard). Her overall role is reduced somewhat in comparison to the first Thor film, but she strolls through London with her sassy energy and wicked grin intact. Rather than put on some epic production, she greets the returned Thor with a sly "How's space?" Following a near-death experience, she drops Ian into a romantic dip before kissing him. There's nothing of substance here, but her vibe is still on point.

'WandaVision' Introduced an Older & Wiser Darcy

With that, Darcy disappeared for eight years. Thor: Ragnarok didn't feature Thor's Earth-based companions. Assuming that her character had suffered the same fate as many other underdeveloped supporting roles – written out by a rotating creative team -- made sense. And then, someone involved with WandaVision made the (frankly) genius decision to incorporate an older, wiser Darcy into the series' secondary plot line. After the town of Westview disappears, S.W.O.R.D. summons a group of various scientific minds to investigate. Darcy now holds a doctorate in astrophysics, the same area of expertise as Jane. That says without exposition how close the two women are, and the profound influence Jane had on Darcy's life. The political science major who was "the only applicant" for Jane's internship pivoted to follow in her footsteps.

But never fear – WandaVision's Darcy retains her essential characteristics. Darcy's never heard of the word "restraint" (or just chooses to ignore the concept), but she now operates with a matured confidence. It makes sense considering her age and experiences, especially as a survivor of the Snap. No longer does she act subserviently as an intern or unofficial assistant; she gives orders and makes her own decisions. And although Darcy contributed in her prior appearances, those moments pale in comparison to the scale and severity of Westview. Wanda Maximoff (Elisabeth Olsen) is one of the most captivating figures to emerge from the MCU, and Darcy's the only one to solve the mystery of the Scarlet Witch. Darcy recognizes the wavelengths hidden inside Westview's CMBR radiation levels, and her creative tenacity with a vintage television gives S.W.O.R.D. a live view of Wanda's sitcom reality. She plays an active role alongside Monica Rambeau (Teyonah Parris) and Jimmy Woo (Randall Park) to try and reach Wanda through the Hex rather than write her off as just a villain. She understands how the Hex rewrote Monica's cells, and she exposes Hayward's (Josh Stamberg) crimes with her slick hacker skills. She helps Westview!Vision (Paul Bettany) realize he isn't the original iteration but reassures him that the love he and Wanda share is real regardless of his origins.

And in a lovely little flourish, she does all of this while feeling "invested" in Wanda and Vision's romance. She applies the context of Wanda's past to the situation and realizes she's watching Wanda's unresolved trauma unfold in technicolor. Although the two never directly interact, Darcy acts out of empathy as much as curiosity.

Darcy's Friendship With Jane Shows Her Evolution

Audiences' last (but hopefully not final) glimpse of Darcy is a brief, but achingly poignant, cameo in Thor: Love and Thunder. Darcy is one of the few people Jane's trusted with the truth of her illness, and watching them interact, their depth of affection is as obvious as their equality as wizened women of the world. She's a dear enough friend to Jane to keep her company during her chemotherapy appointments. Darcy is gonna Darcy, of course; she munches on Hot Cheetos with a recognizable smile, if demurred. Yet she's a voice of reason: she urges her longtime friend not to fight this fight alone. It might be Jane's personal battle, but Darcy reminds her that loving friends surround Jane. This iteration of the character is motivated by feelings as simple and complex as anyone forced to watch a loved one near the end of their life: she wants Jane to take care of herself. Their remaining time together is limited and precious.

What started as a humorous bit part in 2011 stands as Marvel's best example of how to create a consistently well-rounded recurring character. She may remain a steady joke machine first and foremost, but Darcy has forged lifelong friendships and discovered a deeper calling along the way. A girl who refused to die for six college credits now understands the value of life and love. Her honest insight and attention to detail make her the smartest person in almost any room; she's a stellar representation of women in STEM as well as all of us snarky, "weird" girls. The MCU has no shortage of delightful supporting characters, but Darcy is the epitome: a character that her writers let naturally evolve instead of ignoring the potential at their disposal. May Kat Dennings' brilliance long grace our superhero screens.