Long before her debut in the Marvel Cinematic Universe, Carol Danvers became a popular Marvel Comics character when she transitioned from Ms. Marvel to Captain Marvel. Adopting Mar-Vell's alter-ego proved to be successful among critics and fans alike. When Carol Danvers trades in her Ms. Marvel moniker to become Captain Marvel, she gains some well-earned authority and a larger leadership role within Marvel Comics. But it comes at the cost of leaving some of her more developed habits and characteristics behind.
For instance, Carol was once a novelist. In Brian Reed and Giuseppe Camuncoli's Ms. Marvel Special #1, two teenagers discover a book called Binary, written by Carol Danvers. Though the book is seemingly fictional, the story recounts her adventures as Binary after the alien species the Brood altered her cosmic genetics. One of the teenagers, Gavin, turns out to be a superpowered son of an AIM soldier. When Gavin reads Carol's book, his powers accidentally bring some aliens into the real world. When she arrives at the scene as Ms. Marvel, Carol's priority is to ensure everyone's safety and offer kindness to anyone who may have been traumatized. Carol has every right to be upset that her old foes are attacking the city, but she keeps her cool and saves the teens. It's safe to say that Carol would do things differently as Captain Marvel.
After Carol's Kree mentor, Mar-Vell, sacrifices himself against the Phoenix Force in Rick Remender and Renato Guede's Secret Avengers #28, Carol chooses to continue his legacy. In 2012's Captain Marvel #1, writer Kelly Sue DeConnick and artist Dexter Soy debut a new costume for Carol during a battle alongside Captain America against Absorbing Man. After the villain calls her things like "broad" and "Captain America's secretary," she displays anger while making him pay for those comments. After the fight, Cap tells her she should adopt Mar-Vell's superhero name and carry on his legacy. She displays more anger during a sparring session with Spider-Man. The death of Mar-Vell has evidently changed Carol, giving her a harder edge. By taking on the moniker Captain Marvel, she also has his legacy to live up to. But it isn't all bad. The years following the transition see Captain Marvel become a leader of several teams, from the Ultimates to her branch of Avengers in Civil War II. Regardless, some of her best qualities as Ms. Marvel never return.
Brian Michael Bendis and David Marquez's Civil War II shows how much becoming Captain Marvel changes Carol. The sixth issue starts with Ulysses Cain, an Inhuman who forecasts glimpses of possible futures, showing Miles Morales standing over a dead Captain America. Miles kneels on the floor crying, in shock, while Kamala Khan, the new Ms. Marvel, comforts him. Captain Marvel breaks this up and follows her knee-jerk reaction: arrest Miles without hesitation. Iron Man, Captain America, Black Panther, and Ms. Marvel attempt to talk Carol out of this unforgiving nature, but Carol still thinks taking preemptive measures against Miles is essential. Kamala tries to restrain Carol, defending her innocent friend, proving that Ms. Marvel still has a better heart than Captain Marvel.
Carol should understand how difficult it is for Miles Morales to be Spider-Man, as she has also had to follow int he footsteps of a legendary hero. Nevertheless, Captain Marvel doesn't go easy on him. Disagreements turn to battles and deaths after Marvel Comics' second Civil War, greatly due to how Mar-Vell's death affected Carol. Her contemporary thirst for justice is commendable, but the compassion and kindness she showed during her time as Ms. Marvel only earns more appreciation whenever fans revisit her older stories. Unfortunately, the chances of seeing Carol Danvers as Ms. Marvel again are slim to none.