Video games have come a long way from the days of just shooting/hitting things until they die or you run out of levels, with more agency put on you to either abide by a strict set of rules, or try and break them. None are more widespread amongst the heroes of the land than the ancient commandment, "Thou shalt not kill".
It's generally a rule superheroes abide by, including a friendly neighbourhood gymnast and a brooding billionaire vigilante, but it isn't strictly tied to them. Sometimes an undercover cop wavers on that thin blue line, or a well-meaning prince under orders from his father.
Yet, as games have developed from straight forward "scores for kills" to more complex affairs, sometimes the lines blur on what can and can't be done, or what the hero should abide by. Sometimes a character is forced to go against their "one rule", whether through script or the player deciding to push that boundary to see what they can achieve.
Whatever the reason that drives them, it's hard to ignore that some saintly heroes have straight-up killed people.