Actress Nina Dobrev, who played the dual roles of Elena and Katherine in The Vampire Diaries, struggled with the latter role throughout the course of the show. The Vampire Diaries primarily followed the character of Elena Gilbert whilst diving deep into the supernatural realm of witches, vampires, werewolves, and hybrids. The Vampire Diaries co-creator Julie Plec revealed why antagonist and doppelgänger, Katherine Pierce, was killed off the show in Season 5, which tied into reasons why Dobrev struggled with the role in question.
From the get-go, Dobrev’s remarkable acting abilities established Elena and Katherine as two separate entities who were, narratively speaking, dramatic opposites to one another. Elena Gilbert started as a naive, wide-eyed teenager, in love with the brooding and mysterious Stefan Salvatore (Paul Wesley), but her life was tinged with a series of mishaps and personal losses. Becoming a vampire herself at some point in the series, Elena, despite making a host of self-absorbed choices, emerged as the show's protagonist. On the other hand, there was the capricious and conniving Katerina Petrova, who, pushed to the edge by pain, acted as a formidable antagonist to Elena and everyone at Mystic Falls.
Urged by her own motivations, Katherine was a force to be reckoned with, a character fans passionately rooted for despite their not-so-noble intentions. However, the popularity and allure of Katherine came at a great cost, as Plec revealed that CW was heavily concerned by Katherine’s return in The Vampire Diaries season 5, as it could potentially take a toll on Dobrev, as it had during season 2. Dobrev has been forthcoming about the physical demand of the role, as Katherine, despite being physically identical to Elena, has her own separate wardrobe, sonic inflections, movements, and inner motivations. While Dobrev brought Katherine beautifully to life, the fact that Katherine and Elena often shared scenes together made the matter complex and physically exhausting, as filming for arduous hours with a body double while completing redoing certain parts of a scene could potentially lead Dobrev to burnout.
It is important to acknowledge that while The Vampire Diaries posited complex and interesting storylines, along with characters to root for, such as Caroline and Bonnie, it was Katherine’s presence that helped boost the supernatural drama’s reputation. In fact, much of season 2’s success hinged on the tussle between Elena and Katherine and the stark contrast between two characters played to perfection by Dobrev. What made the dynamic more interesting was how Katherine was able to mimic Elena whilst also retaining her individual quirks for the audience’s eye, adding a fresh layer of thrill and the presence of a compelling antagonist in the lives of Damon, Stefan, and Elena.
In the end, playing both characters, especially in the same scene, become too tricky, as it would mean constantly shifting from one character mindset to the next for Dobrev. In an interview (via EW), Dobrev noted how it was “crazy” in terms of shooting schedules and scenes with herself for the dual roles, although it was a “wild learning experience” for her as an actress. Moreover, Dobrev imbued Katherine with considerable depth in The Vampire Diaries, as the wavy-haired, manipulative antagonist is a 500-year old vampire running away from her own demons and blood-splattered past. While Elena went through her own journey in the show, playing Katherine demanded a more nuanced understanding of her 500-year-old past and her ever-fluctuating allegiances, which might’ve been too much for Dobrev after playing Elena throughout every season of the show.