The Avengers are often thought of as the heroic ideal in the Marvel Universe. They're the defenders of the Earth, the media darlings that everyone looks up to. The Avengers have an image as squeaky clean heroes, but the business of saving the world isn't for the faint of heart. Sometimes, things have to be done that don't sit right with everyone, prompting the Avengers to keep some grim secrets over the years.
Source：https://www.cbr.com/avengers-dark-hidden-secrets/
