10 Crazy In-Universe Rules MCU Characters Must Follow

Before he became a badass sorcerer, Stephen Strange was a medical doctor who, like all doctors, adhered to the field's code of ethics known as the Hippocratic Oath.

The most salient and oft-repeated part of the oath is "do no harm," a mantra which Strange clings to even once he takes up the mystic arts.

After killing one of Kaecilius' (Mads Mikkelsen) followers, Lucian (Scott Adkins), in the original Doctor Strange film, he expresses tremendous remorse, reiterating to the Ancient One (Tilda Swinton) that he took an oath to save lives, not end them.

Though Strange has certainly softened his no-harm stance over the years as the world's threats have become greater and more multiversal, he generally still only directly kills his foes when he absolutely, positively has to, more often using magic to subdue them.

Granted, the mere act of fighting itself causes harm if you want to get technical, but let's face it, he's usually protecting either himself, his fellow Avengers, or the Earth itself whenever he gets forceful, right?

Considering that most of Strange's fellow Avengers won't bat an eyelid when it comes to taking lives, this trait differentiates Strange in a way that isn't talked about nearly enough.