The following contains spoilers from Secret Invasion Season 1, Episode 1, "Resurrection," now streaming on Disney+.

The series premiere of Secret Invasion is a well-paced thriller delving into the Marvel Cinematic Universe of spycraft. Samuel L. Jackson's Nick Fury returns to Earth to help his allies deal with a faction of militant Skrulls who want to take Earth for themselves. Fury is fighting a war, and fan-favorite MCU human hero Maria Hill, played by Cobie Smulders, is killed by a Skrull wearing Nick Fury's face. In stories based on comic books, death doesn't always mean the end for a character. But if Maria Hill is truly gone, it's a sad day for Marvel fans.

Maria Hill first appeared in Avengers as an agent of S.H.I.E.L.D. who worked closely with Fury and Clark Gregg's Phil Coulson. Given that the latter character died, Hill became the new go-to human helper for Earth's Mightiest Heroes. She was on the front lines when S.H.I.E.L.D. fell in Captain America: The Winter Soldier and found a new gig at Avengers Tower in Age of Ultron. She also appeared that year in Agents of S.H.I.E.L.D., working with the revived Coulson to fix up the helicarrier that saves the people of Sokovia. The show was still trying to keep pace with the larger MCU, and even when the connection to the film's universe is less tenuous, Smulders' Hill shows up to add some Marvel cred, like her appearance in Moon Girl and Devil Dinosaur. Lastly, just because Maria Hill may be dead, it doesn't mean Cobie Smulders is done on Secret Invasion.

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Why Maria Hill Is So Important to the MCU

Nick Fury and Maria Hill side by side

Maria Hill doesn't have any superpowers. She is, essentially, Black Widow without the nifty shock bracelets and none of the Red Room trauma. She's handy in a fight and always ready to scrap. When Hawkeye and other people mind-controlled by Loki stormed the helicarrier's bridge in Avengers, she didn't hesitate to fight back. Similarly, when Ultron first attacked the Avengers, she contributed more to the fight than Widow or Bruce Banner did. Still, unlike the rest of the team, she was adept at keeping their operation running. She had both the tactical skill and administrative knowledge to keep the Avengers on task and efficient.

While her backstory remains a mystery, Maria Hill presumably has been in the fight far longer than any of the Avengers. She was a part of S.H.I.E.L.D. for her entire career before it fell. Between Avengers: Endgame and Secret Invasion, the Avengers compound was destroyed, Iron Man was killed and the rest of the heroes scattered. Hill is now working for S.A.B.E.R., S.W.O.R.D. or whatever other intelligence apparatus exists for spies like her. She's also been fighting longer than Fury, at least post-Blip.

The loss of Hill is likely meant to isolate Fury further, though Smulders' performance in the episode makes that fact hurt even more. The scene in which she tells Fury he's lost a step is one of the highlights of the episode. Smulders is able to make it clear that Hill is still loyal to her friend and mentor. Yet, she also knows this is not a game. If Fury is compromised emotionally, it could result in disaster. She's proven right when the attack happens, and she's gunned down by Kingsley Ben-Adir's Gravik wearing Fury's face. Maria Hill is as much an original Avenger in the MCU as anyone else in that film wearing a skin-tight suit.

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Cobie Smulders Made an Underdeveloped Character Into a Person Fans Love

Cobie Smulders as Maria Hill with a scar on her cheek in Avengers.

When the MCU's flagship team first assembled, Cobie Smulders was best known for playing "Aunt" Robin on How I Met Your Mother. The character was introduced in the comics in 2005, and her appearance in Avengers was essentially an Easter egg. Writer and director Joss Whedon mostly used Hill to deliver exposition. She wasn't a fully-realized character; however, that changed over brief appearances on Agents of S.H.I.E.L.D. and in the Avengers sequels. Smulders was able to imbue Maria with gravitas, charm and emotion. Ironically, the series premiere of Secret Invasion may be the best Maria Hill story in the MCU. She has surpassed her mentor and colleague. Perhaps if she'd been running the operation instead of Fury, everyone might have come out alive.

Since the central antagonists in the series can shape-shift, Smulders may appear again. A Skrull may impersonate her to give at Fury or confuse his allies. It's also possible that some sci-fi magic can revive Hill, allowing Smulders to remain one of Marvel's best utility players. However, if Secret Invasion is her swan song in the MCU, she leaves behind a legacy larger than the size of her role in each appearance. Even with 11 appearances across movies and TV, she is one of the MCU's most under-utilized characters. In fact, if Fury had taken her advice and just gone home, Secret Invasion would still be a fun series to watch with Hill in the driver's seat.

Secret Invasion debuts new episodes Wednesdays on Disney+.