Captain Marvel: 10 things to know about Captain Marvel before her MCU debut
Civil War
In the 2006 “Civil War” storyline written by Mark Millar and illustrated by Steve McNiven, Carol is part of the immediately rescue/cleanup efforts when a minor villain blows up an elementary school while battling a minor group of heroes called the New Warriors in Stamford, Connecticut, resulting in around 700 deaths. She then uses her blogging skills to advocate for the Superhero Registration Act.
Carol joins Tony Stark’s side in the conflict, becoming a licensed hero working as a federal agent as part of the Initiative.
She also is a participant during the power plant confrontation organized by Stark against Steve Rogers/Captain America’s anti-registration forces in a battle which killed Bill Foster/Goliath.
Following the arrest of Captain America and Stark’s elevation to SHIELD Director, Carol assumes command of the (legal) Mighty Avengers for a time.
This storyline was adapted into the MCU’s Captain America: Civil War, though the setting of the initial incident was changed to the city of Sokovia (in Avengers; Age of Ultron) and Johannesburg, South Africa, and the casualty count (at least in Johannesburg) was somewhat lessened.