Last week, filmmaker Joss Whedon confirmed what many Marvel movie fans already assumed to be true: he's through. He's done with Marvel movies, and the break with the studio was swift, decisive and final. The development came along with the end of production on "Avengers: Age of Ultron." But the split wasn't acrimonious, it was expected.

"I made a completely clean break -- not because we had a falling out -- just because I was like, 'I can't...' If I was still there going, 'Well, here are my thoughts on this film,' I'd be there every day. I wouldn't do anything else because there are a lot of films, and it is a lot of fun. It's very seductive. When you can put your little fairy dust on things and just improve them slightly, and they actually listen to you... I was a script doctor for a long time, and the part where they listen to you was very rare; so it was very important for my own self to go 'we can still be friends,' but..."

Joss Whedon's day-to-day involvement with the Marvel Cinematic Universe included more than just writing and directing 2012's "The Avengers" and 2015's "Avengers: Age of Ultron." He also consulted on scripts, even rewriting scenes in "Thor: The Dark World," and helped get Marvel's "Agents of S.H.I.E.L.D." off the ground by co-writing and directing the first episode. Below, we examine his greatest contributions to MCU lore.

The Death & Life Of Phil Coulson



Phil Coulson before being killed in The Avengers



Debuting in 2008's "Iron Man," Clark Gregg's mild-mannered S.H.I.E.L.D. agent has been a part of the Marvel Cinematic Universe from the very beginning. And we can't credit Whedon with Coulson striking a chord with fans; his deadpan humor was a highlight of 2011's "Thor" and he appeared in a few of Marvel's short films before "Avengers." But with "Avengers," Whedon took a character that was already working and made him iconic. Whedon established Coulson as a Captain America superfan, one with a vintage set of Cap trading cards, and he gave him friendly banter with Pepper Potts that hinted at a possible girlfriend (a cellist). But, most importantly, Whedon gave Coulson a heroic moment against Loki -- and he also gave him a tragic, violent death. Coulson's death really rallied fans around the character, sparking a Coulson Lives social media movement. The outpouring of love eventually led to the character's resurrection and him becoming the lead in "Agents of S.H.I.E.L.D.," a series that Whedon helped put together with Clark Gregg's agent in mind.

Maria Hill





Legend has it that Cobie Smulders was Joss Whedon's top choice to play Wonder Woman back when the filmmaker was tasked with bringing DC's Amazonian warrior to the big screen. That film fell eventually fell through, but Whedon apparently kept the actress on a short list because she ended up landing the role of Maria Hill in 2012's "Marvel's The Avengers." Whedon's choice has proven to have a lasting impact; like her S.H.I.E.L.D. co-workers Nick Fury and Phil Coulson, Maria Hill has racked up a number of appearances in the Marvel Cinematic Universe. In addition to Whedon's two "Avengers" films, she's appeared in "Captain America: Winter Soldier" and she's one of the few film characters to appear on the small screen, with Smulders playing Hill three times on "Agents of S.H.I.E.L.D."

New Avengers





Similar to introducing Maria Hill in "Avengers," Whedon introduced even more new characters in "Age of Ultron" that will most likely play a large role in the MCU in Phase Three. While Aaron Taylor-Johnson's Quicksilver didn't make it out of "AOU" alive, Elizabeth Olsen's Scarlet Witch and Paul Bettany's Vision did -- and Whedon also made them full-fledged Avengers. Whedon also promoted franchise vets Falcon (Anthony Mackie) and War Machine (Don Cheadle) to full-time Avengers, setting in place the team line-up that will appear in this year's "Captain America: Civil War." And while Whedon wasn't responsible for casting Bettany, it was the writer/director's idea to elevate the actor's role from just voicing Tony Stark's A.I. butler J.A.R.V.I.S. into fully embodying the Vision.

Loki





No, Whedon can't take credit for casting Tom Hiddleston as the god of lies, nor did he write or direct the character's debut in "Thor." Whedon did, however, build upon what already existed to create what is consistently called the most complex villain in the MCU. Whedon's knack for Shakespearean dialogue and knowledge of centuries-old curse words played harmoniously with Hiddleston's captivating and grand performance, and Whedon gave the character an even grander plan than the one seen in his debut. Whedon didn't ease off of the familial drama, either, making sure that Thor and Loki's heartbreaking relationship got sufficient screen time. More so than in "Thor," Loki felt dangerous in "Avengers" -- after all, he put an alien staff through Agent Coulson's heart. Without "Avengers," one has to wonder if the character's actions in "Thor" would have been enough to make him the definitive big screen Marvel villain.

Steve vs. Tony





As evidenced by the "Captain America: Civil War" trailer, we're about to get a whole movie built around the conflict between Captain America and Iron Man. But let's not forget the man that planted those seeds of conflict years ago: Joss Whedon. As the man responsible for "The Avengers," Whedon was in charge of showing the first meetings between pretty much every Marvel movie hero. Iron Man calling Thor "Point Break," Black Widow recruiting Bruce Banner, Coulson withholding fanboy glee in the presence of Cap -- Joss laid the foundation of so many MCU relationships. The real spark, though, happened between Robert Downey Jr. and Chris Evans, specifically in the Helicarrier lab moments before Loki's attack. That's when their ideologies first clashed and, in the ensuing melee, when their begrudging trust became a (mostly) unbreakable bond. The pair were tested again in "Avengers: Age of Ultron" when Stark was forced to confront his rogue A.I., which he created for reasons that Steve didn't exactly agree with. Remember, Steve was so mad that he ripped a log in half? Imagine the log is a suit of armor, and you basically got the "Civil War" trailer.

Mark Ruffalo as Hulk





Whedon's first act as "Avengers" director remains his most definitive one -- and most likely will for a long time coming. Rumors of Joss Whedon's initial involvement were tied with reports of previous Hulk Edward Norton's departure. And then came the one-two punch at 2010's CCI in San Diego: Joss Whedon would direct "Avengers" and Mark Ruffalo would become the new Bruce Banner. This decision, quite possibly Whedon's first as the "Avengers" head, proved to be a massively popular one. Audiences responded very well to Ruffalo, better than they had to previous big screen hulks Eric Bana and Norton, igniting near constant calls for the character to get another solo film. Whedon also put Ruffalo front-and-center, focusing much attention on the conflicted man behind the monster. And he even gave Hulk a catch phrase that now ranks up there with "Hulk smash" -- "I'm always angry." Ruffalo isn't going anywhere, either; he appeared in the post-credits scene of "Iron Man 3," returned for "Avengers: Age of Ultron" and will star alongside Chris Hemsworth in "Thor: Ragnarok." While we might not see any solo Hulk films any time soon, Whedon's Hulk casting continues to find ways to affect the MCU.