Chris Evans has played Captain America since the character received his own eponymous film in 2011. Although there’s some indication the actor might no longer play the hero following Avengers 4, Evans has explained what draws him to the First Avenger.

An interview with Evans appears in the upcoming book Marvel Studios: The First Ten Years. When asked why the role appeals to him, Evans responded, “Steve Rogers is a man who wants very much to do good and serve his country in World War II, but he’s been rejected from the Army for having asthma and other health challenges… Because of his good values and morals, Steve is chosen by a man named Dr. Erskine for an experiment to create a ‘Super Soldier.'”

“He is injected with a serum that turns him into Captain America – and Dr. Erskine knows Steve won’t take advantage of the gift of power and will always protect the weak,” he continues.

Ever since filming for Avengers: Infinity War and its sequel Avengers 4 began, rumors have abounded that the two films would serve as the final adventure for many of the Marvel Cinematic Universe’s longest-serving heroes. While the future of many characters is still up in the air, Evans previously said that he wouldn’t be opposed to returning to play Captain America. After all, the actor’s contract with Marvel was up after Infinity War, but he extended it for Avengers 4, when it was decided to split the movie into two. However, Evans has also said he would not return to the role following the upcoming film, so it’s unclear exactly what will happen.

Marvel Studios: The First Ten Years will be released on Nov. 20.

The sequel to Avengers: Infinity War will release on May 3, 2019. Directed by Joe and Anthony Russo, the film stars Robert Downey Jr., Josh Brolin, Mark Ruffalo, Tom Hiddleston, Chris Evans, Chris Hemsworth, Jeremy Renner, Chris Pratt, Elizabeth Olsen, Sebastian Stan, Benedict Cumberbatch, Paul Bettany, Samuel L. Jackson, Cobie Smulders, Benedict Wong, Zoe Saldana, Karen Gillan, Vin Diesel, Dave Bautista, Pom Klementieff, Scarlett Johansson, Paul Rudd, Evangeline Lilly, Tom Holland and Anthony Mackie.