In the comics, Dane Whitman is the identity of the Black Knight, a sword-wielding superhero who has a dark curse and has been a part of the Avengers and other superhero groups.

The comics tell that the Whitman family and ancestors have worn the mantle of the Black Knight for decades and Dane is currently the bearer of that tradition. Owner of the Ebony Sword, this artifact has a curse every time it kills itself and drives its bearer mad, although in the comics Dane Whitman was able to put an end to this and use the sword to do good.

By not officially introducing himself as the Black Knight and having his origin story, Dane Whitman (Kit Harrington) will have a better future in the MCU and will eventually become this superhero.