One of the most fascinating mythologies within the greater mega-mythos of the Marvel universe is that of the legacy of the Iron Fist. Since - like the abilities of the Sorcerer Supreme - one earns these powers instead of having them thrust upon them, many people have taken up the mantle of the titular martial arts superhero.
Although Danny Rand is the first to have made his presence known to the wider Marvel universe, the line of Iron Fists have been around for a VERY long time, and have as such featured some great warriors. Despite the many names attached to the line throughout the character's history, we still don't know everyone who has inherited the mantle. So apologies if it seems like your scribe is jumping entire centuries here, just working with what I have.
With that said, let's take a good hard look at every named character so far who has inherited the powers of Shou-Lao and become the martial arts champion, Iron Fist!
10. Quan Yaozu
No better place to begin than at the beginning. The VERY beginning, at that, with the very first Iron Fist known as Quan Yaozu.
We don't know that much about him, since he exists purely as mythology in the world of Iron Fist. It isn't like they gave him his own entire series (maybe if Iron Fist was actually a halfway successful property financially speaking, but alas).
What we do know is that he was one of, if not the earliest holders of the mantle, given to him by the elders of K'un-Lun to protect it and the other Seven Capital Cities of Heaven from a recently discovered, brutally hellish, eighth city.
When the time came to seal off the eighth city forever, Quan elected to stay on the other side to make sure it closed properly, condemning himself to death at the hands of the city of very pissed off demons.