In 2006, Marvel Comics kicked off a line-wide event called Civil War. The story was unlike anything Marvel had ever published. Writer Mark Millar ditched the usual earth-shaking villainous schemes in favor of a topical, timely, and far more personal drama. The titular war was based on a moral divide between Marvel's superheroes, in which both sides had a valid argument. Civil War was a quagmire of ideologies, where nothing was ever simple and principles propelled its participants down ever-slippier slopes. There was no perfect solution, and that's why it was so compelling.

Spider-Man likes to remind us that superheroes don't have the luxury of irresponsibility. But the flip side — government oversight — creates a whole new set of problems, especially when the smartest men in the world are dreaming up ethically questionable ways to enforce the new world order. In case you couldn't tell, superhero life in the 21st Century is a complex endeavor, and this is the stage that Phase 3 of Marvel's Cinematic Universe plays out on, starting with Captain America: Civil War.

Like most adaptations, when all is said and done, the big screen version of Civil War will likely differ wildly from the comic that inspired it. Based on what we know so far, here are the 12 Differences Between the Comic and the Movie.

The Inciting Incident

In the comic book, a group of young, D-list superheroes called the New Warriors attempt to apprehend an out-of-their-league villain named Nitro while filming a reality TV show in Stamford, Connecticut. Things go sideways when Nitro uses his powers to create an enormously powerful blast, destroying several city blocks and causing the deaths of some 600 civilians, many of them children. Public sentiment turns on superheroes practically overnight, and the U.S. government is pressured to ensure that superheroes receive training and oversight, so that this kind of foolish irresponsibility can be prevented.

The New Warriors don't exist in the Marvel Cinematic Universe, so the events of Captain America: Civil War are seemingly instigated by the collateral damages that have been resulting from the Avengers' missions. After the casualties and property damage from the Battle of New York and the fight for Sokovia (and likely at least one more incident), it's decided that the Avengers need to be held to higher standards of accountability. Some heroes will agree with this decision of course, and others won't.

Characters Involved

In the comics, virtually every member of the Marvel Universe is forced to pick a side. Through a huge collection of tie-ins and special issues, every superhero — and most of the super-villains — are at least affected by the war, even if they don't directly participate in it.

The size of the movie's cast is impressive for a solo Marvel character's flick, but it still pales in comparison to the roster from the book. Most noticeable will be the absence of the Fantastic Four; Reed Richards played a huge role on the pro-registration side of things, working alongside Tony Stark for the entire story. Fox owns the screen rights to the Fantastic Four (cue groan), and has no interest in sharing custody of the characters with Marvel.Marvel claims that Mark Ruffalo's Bruce Banner/Hulk will be MIA for this outing, but there have been rumors to the contrary. We can definitively say one Avenger who's not in it, and that's Thor. He's in Asgard, trying to sort out who's been gathering the Infinity Stones — and getting ready for next year's Thor: Ragnarok, of course. Which, incidentally, Hulk is slated to be a big part of.

Why Captain America is Anti-Registration

The original story found Steve Rogers balking at superhero registration for a number of reasons. Foremost among them was the outing of heroes' secret identities, which Rogers saw as a time-honored tradition that kept them out from under government control. This violation of civil liberties didn't sit well with him, but the straw that broke the camel's back was when S.H.I.E.L.D. revealed its intentions to hunt down unregistered heroes — and they expected Cap to lead the charge.

Civil War ties in with the last movie, The Winter Soldier, by continuing the story of Steve Rogers and his lifelong best friend, Bucky Barnes. Bucky was brainwashed and turned into a villainous assassin in that film, but judging from what we've seen so far, Rogers has helped him recover his memories and heroic nature. The movie ties in the Civil War with Bucky's fugitive status; as a man with a long record of criminal activities, he's a very wanted man. We also imagine that the government trying to hold the heroes accountable for damage that was actually caused by villains doesn't sit well with Cap. But it's his loyalty to his friend that tips the scales for him, causing him to go rogue.

And of course, the none of the MCU's heroes have secret identities to speak of, though that will almost certainly soon change with Spider-Man making his way onto the scene. More on him in a bit.

Which Side They're On

In the movie, the anti-registration side is filled out by Captain America, Falcon, Winter Soldier, Hawkeye, Scarlet Witch, and Ant-Man. Cap's love interest Sharon Carter, aka Agent 13, also sides with him. The pro-registration side is comprised of Iron Man, War Machine, Black Widow, Vision, and the newest player on the scene, Black Panther.

In the comic book, the sides were similar, only much, much bigger. Hawkeye and Scarlet Witch sat out the conflict for reasons dating back to a story called Avengers Disassembled. Vision was on Cap's side in the book, while the movie has him on Iron Man's team. Many fans were surprised to find that Black Widow sides with Iron Man in the movie, as she's always been a close ally to Captain America (they were pretty chummy in Winter Soldier) and her relationship with Tony Stark has been shaky at best. The movie will no doubt explain her choice, but it's not a huge stretch since she sided with Tony in the comic book.

Black Panther was against the new U.S. legislation in the comic, but chose to keep himself and his nation Wakanda out of most of the fight. Marvel has described his part in the movie as a similar wildcard, but later clips from the film show him siding with Iron Man. The jury's still out on him.

The Legislation

In the comics, the new law is known as the Superhero Registration Act, or the SRA. It's sparked by an activist named Miriam Sharpe, the furious, heartbroken mother of one of the children killed in Stamford. When she points her grief and rage at Tony Stark, he feels a tremendous responsibility to make sure there's never another disaster caused by the careless use of superpowers. An argument could be made that Sharpe even manipulates Tony to some degree, playing on his guilt while the moral and physical cost of the war escalates.

In the movie, the SRA is represented by the Sokovia Accords. The Accords are named after the location of the Avengers' massive battle at the end of Age of Ultron — a fight that cost many human lives. It's possible that Tony Stark falls in line with the Accords because he feels guilty about Sokovia. It was his creation (Ultron) that caused so much death and destruction, after all.

Who Enforces the Legislation

It fell to S.H.I.E.L.D. to enforce the Superhero Registration Act in the comic book, with superheroes like Iron Man, Reed Richards, and Hank Pym functioning as the SRA's public face — and its masterminds, in many ways. Though that organization as we knew it fell back in Winter Soldier, there was a S.H.I.E.L.D.-like presence at the Avengers' upstate New York headquarters at the conclusion of Age of Ultron. Could the brainchild of Nick Fury be back in play?

Not quite. In Civil War, the Sokovia Accords are enforced by a government body called the Joint Counter-Terrorist Center. William Hurt's General "Thunderbolt" Ross returns for the first time since 2008's Incredible Hulk to speak for the JCTC. Ross appears to be the human symbol of the government's interests in protecting its citizens — at least until Iron Man takes up the charge.

What the Bad Guys Are Up To

Writer Mark Millar loved to throw big twists into the Civil War story, and one of them features the enlisting of some of the worst of the worst villains in the Marvel world to fight for the government (Suicide Squad-style) by hunting down unregistered heroes. The irony of these baddies being allowed to hunt down their mortal enemies with the law on their side is lost on no one. One hero in particular takes the brunt of the supervillains' brutality, and remarkably, said villains are allowed to get away with it.

By all indications, this particular plot element plays no part in Captain America: Civil War. This is probably due to the streamlined constraints of a two-hour film and the fact that the majority of Marvel's villains are either too big (Thanos, Loki) or too dead (Red Skull, Whiplash) to participate in the conflict.

Spider-Man's Role

Having recently joined the Avengers and benefited from a brand new, armored Spidey-suit courtesy of Tony Stark's deep pockets, Peter Parker was a relatively easy sell on Tony's pro-registration sentiments at the time. In a genuinely shocking twist, Tony actually convinced Peter to publicly unmask at a press conference, as a show of good faith to restore trust in superheroes. Peter had guarded his secret identity more fiercely than any other hero, and his sudden public revelation changed that forever (or at least until it was predictably retconned a year later). When the fight escalated and the truth came to light about the extreme measures Tony, Hank, and Reed had gone to (see the next two entries) to enforce the SRA, Spider-Man jumped ship and signed on with Cap.

The Wall-Crawler's place in the movie is guaranteed to be very different. Up-and-comer Tom Holland is taking over the role, debuting a brand new take on Spidey that depicts him as a young high school student. And with this being Holland's introduction to the Marvel Cinematic Universe (thanks to a highly-publicized "let's play nice" deal with Sony Pictures), there's no way his character arc could follow the same trajectory as the older, adult, married Peter Parker of the comics. Also consider that Holland was cast late in production, so his role can't be a terribly vital one.

What fans really want to know is if the Spider-Man of the film will pick a side — and maybe even show up in the big battle royale at the airport. For that, we wait and see.

The Superhero Prison

This brainchild of the Fantastic Four's Reed Richards was dreamed up as a place for incarcerating unregistered superheroes, as well as those who fought against the SRA. It was a maximum security, future-tech facility located in another dimension — the Negative Zone, where the FF tends to spend a lot of its time. The prison became a place where both super-villains and superheroes were housed side-by-side, and you can imagine how that went.

With the Richards family unavailable in the film world, the Negative Zone is off-limits, as is its super-max jail. This aspect of the comic will likely be ignored.

Thor's Clone

Thor was AWOL for the entirety of Civil War, busy with the Asgardian end-of-the-world scenario called Ragnarok. In his absence, Iron Man's pro-registration team was in need of a heavy-hitter, so Tony, Hank, and Reed had yet another big idea: clone Thor and implant the clone with cyborg technology so they could control it. As you might expect, our brainy trio got caught up in the excitement of the science and invention of creating the thing, and failed to account for the moral and human cost, causing one hero to pay the ultimate price. Subsequently, Reed's wife Sue left him with her brother Johnny in tow. (They worked things out later though, because comics.)

Don't expect to see a Thor clone on the big screen; it's a bit too out-there (read: silly) for movie audiences.

Character Death

In Civil War, the first casualties were most of the members of the New Warriors. Later, Thor's rogue clone murdered an Avenger named Goliath, a hero who shared Giant-Man's powers to enlarge himself to gigantic proportions. At the end, after all was said and done, Captain America was assassinated.

Rumors have been all over the place as to who will die in the movie, with everyone from War Machine (who doesn't look so good in that shot from the trailer) to Scarlet Witch supposedly on the chopping block. But the most likely candidate is Captain America himself, especially since this is his movie. Don't worry, though. Chris Evans is contracted up through the two-part Avengers: Infinity War, so if Cap bites the big one, he'll walk it off.

The Outcome

As the story reaches its crescendo, superhero numbers swell in Cap's favor in the comics, mostly thanks to the gestapo-like tactics employed by SRA supporters. Captain America's forces are on the cusp of victory when he sees the damage this war has done to New York City, and he realizes that public opinion is fully behind registration. He surrenders, and he's assassinated days later while in S.H.I.E.L.D. custody. As the unofficial winner of the war, Iron Man becomes the new Director of S.H.I.E.L.D., and he and his allies implement something called the "50 State Initiative," which puts a superhero team in all 50 states.

The Marvel Cinematic Universe isn't as big a place as the comics world, so the movie's consequences can't possibly top those of the comic in terms of scope. Still, directors Joe and Anthony Russo have promised that their movie will have a massive impact on the MCU, even bigger than the dismantling of S.H.I.E.L.D. at the end of Winter Soldier. They also warn viewers to "expect a very dramatic ending that will be controversial for a lot of people." In other words, death is coming, and it's bringing along some major shakeups to the status quo.

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Whatever happens, you can take comfort in knowing that (at least most) of your favorite characters are going to iron out their issues (and return from the dead) in time for 2018's Infinity War. Which aspect of the original comic are you most going to miss in the movie adaptation? How big of an impact do you think Civil War will truly have on the future of the MCU? Be sure to let us know in the comments below.