Civil War was a massive Marvel crossover event running from 2006 to 2007 and tied into virtually every Marvel comic including cosmic ones, like Nova, and quirky teen ones, like Runaways. The comic begins with the New Warriors (a team of perpetually C-Listers) fighting a group of supervillains to garner better ratings for their reality TV show, which leads to the villain Nitro blowing up a school in Stamford, Connecticut leading to many civilian casualties. This leads to Tony Stark, Reed Richards, the Avengers, and SHIELD supporting the Superhuman Registration Act, which bans secret identities, implements mandatory training for young heroes, and makes superheroes agents of SHIELD. This is opposed by Captain America, who doesn’t want to hunt down his fellow heroes, and the conflict begins as all the heroes of the Marvel Universe must either choose the Pro-Reg or Anti-Reg side.
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