From the moment she was offered a role in Secret Invasion, Cobie Smulders knew she’d be saying goodbye. She’s held on to the twist for well over a year—fashioning “a whole shuffle-step dance” at press events, carefully talking around her fate in the MCU’s newest series without giving anything away. Now she can at last discuss it, and breathes a palpable, slightly melancholy sigh of relief in her first interview. “Finally it’s out there,” she tells me over Zoom. “I’ve been well trained—yeah, I’ve had to keep secrets.”

Spoken like a true Marvel veteran. Smulders has been part of the MCU machine for more than a decade, going back to her first appearance in 2012’s original Avengers movie as Maria Hill, the right-hand woman to Samuel L. Jackson’s SHIELD director, Nick Fury. The sharp, levelheaded, analytical character popped up in many more movies as the MCU’s mythology evolved and its heroes came and went; eventually, she became one of the last Phase One figures standing. Hill rarely drove the action, but took part in several of the franchise’s most indelible moments as a crucial strategic contributor, and was set to make her big return in Secret Invasion, the Disney+ series centered on Fury. This turned out to be her last chapter—well, presumably.

Hill dies at the end of the series premiere, which is set in Moscow. She’s reunited with a weathered Fury as they prepare to stop Gravik (Kingsley Ben-Adir) and his team of rebel Skrulls—shape-shifters who’ve invaded Earth and can take on the appearance of any human. An attack against Fury and his allies in a town square culminates in Hill getting shot by a Skrull who’s taken on the appearance of Fury. Hill’s dizzying final few seconds of life find her grappling with the possibility that her closest ally has betrayed and killed her. When the real Fury realizes what’s happened, he tells her it wasn’t him, but it may be too late. In that ambiguity, the series’ conflict is set in motion, fueled by Fury’s grief and quest for revenge.

We’re now firmly in the era of multiverses and time-jumps, so question one: Is Hill really dead? “I mean, I didn’t know I was an alien in Spider-Man,” Smulders cracks, referencing the twist of her appearance in Far From Home. “There is a multiverse now, so anything is possible. But I’m pretty sure this is it.” (As for rumors that she appears in this fall’s The Marvels, Smulders denies them: “I don’t know anything about that.”) During our conversation, Smulders speaks of Hill’s fate with a certain finality, having made peace with the fact that this is likely the end. “It felt and it feels strange,” she says. “Maria Hill’s passing is very real, and it’s shocking, and it feels very human.” She adds, “It was a sad day.”

Smulders describes her role across the MCU as a kind of “fly on the wall” in some of its biggest and most iconic scenes—watching the likes of Robert Downey Jr.’s Iron Man, Mark Ruffalo’s Hulk, and Chris Hemsworth’s Thor just go at it from the sidelines. When she was first cast, the star was still deep in How I Met Your Mother, more accustomed to bar banter and punch lines than CGI and stunts. “Everything was so new to me. Any action sequence was really new to me,” she says. “I knew that the Avengers film was going to be a big film, and I was contractually obligated for a few more [projects]. I just didn’t know where we were going.”

Hill stuck around, and Smulders accepted the confines of the part as a fresh acting challenge. “It has been about creating, finding what my place is in that world,” she says. “Maria Hill has always lived in the background and in the shadows. I’ve created my own world for her while all this other flashy stuff is going on onscreen. I’m creating this world for her that isn’t being shown.” A big part of that, of course, has to do with the bond between her and Nick Fury. Smulders originally auditioned with Jackson, a collaboration that’d deepen in movie after movie. (“I’ve enjoyed every minute with him on set.”) But she loved playing in the sandbox of a world with which she was entirely unfamiliar, and which came to feel like a place in which she belonged.

Secret Invasion’s pilot strips the CGI-driven set pieces that have characterized much of Smulders’s time on Marvel sets. It captures more day-to-day life and focuses on the intimate, fraught interactions between her and Fury as they’re tenuously reunited. One poignant bar scene finds Hill calling Fury out on his decision to come back after a long time away, with the character telling him, “There is no shame in walking away when the steps are uncertain.” It’s the kind of material that Smulders had been imagining off-camera, and relished finally getting the chance to play. Even playing her demise was a first. “I don’t think I’ve ever died on camera,” Smulders says. “I got a real death scene!”

For fans of the character, the feeling that she was coming into her own just as she was killed off has led to a divisive reaction to the death. Does Smulders wish she’d had more scenes like those in the Secret Invasion pilot to play in her time as Hill? “I mean, listen, it would’ve been great,” she says. “Of course I would’ve loved to do more, but I trust that Marvel is doing the storyline that they think is best.” Smulders is used to strong viewer responses, given the outcry that followed the How I Met Your Mother finale. “I feel bad if their reaction is negative and they don’t like it, but I think that there is also something positive to take away from that,” she says. “They were so connected to the story and these characters that they cared. That is beautiful and wonderful.”

There was nervousness around news of Hill’s death potentially leaking. The script wasn’t printed out, of course—Marvel’s learned not to do that by now—and as they got to filming the big scene just north of London, you could feel the paranoia. A few drones flew overhead; they were chased down to ensure nothing was sussed out. (“They did find somebody, so sorry to that person,” Smulders says vaguely.) It took multiple days to shoot—with the explosions and initial reactions to the attack orchestrated by Gravik coming first, followed by Smulders’s big moment. She did three takes of Hill’s last gasp. It was the last thing Smulders ever filmed for the show—and as Maria Hill.

The squib attached to Smulders’s stomach activated where the character was shot, prompting Smulders to instantly react as if she were losing breath. She looked Jackson in the eye each take, very precisely playing the beats of what Hill had gleaned from the situation by the time she’d passed on. The mood was emotional. Smulders was saying goodbye to a role she’d been playing for more than 10 years at the same time that she was trying to nail a tricky, ambiguous, deeply emotional scene.

“To have Fury see himself, to know that Hill thinks that Fury shot her—that’s the pain of that moment,” Smulders says. “I like to think that she, by the time she passed, knew it wasn’t him. Initially, it’s terrifying and so confusing. But I’d like to think she got there.”

When Smulders is asked what she’ll miss the most, her memories take her back to Hall H of San Diego Comic-Con, where she interacted with feverish and devoted fans. “What I love the most are the kids who are really in the world—they are living it, playing it out as different characters. It’s been really cool to be a part of that,” Smulders says. She’s holding on to a few Maria Hill action figures herself as she enters the next phase of her career. She raises her arm with a smile, as if proudly gripping a mini Hill. “I will be a grandma being like, ‘This is me. I was in these films.’”