Iron Fist is among the top few martial artists in the world. He was trained in the mystical city of K'un-Lun, which is accessible to our plane of existence once every ten years.
Becoming the best fighter in K'un-Lun gives one the right to face Shou Lao the Undying - a dragon that stands guard over a big bowl/pot that contains its own heart - and (if you defeat him) become Iron Fist.
Iron Fist
did defeat the dragon. He then slammed his hands into the heart of the dragon ("Heart of the dragon!" is his favorite exclamation.
![Laughing :lol:](./images/smilies/icon_lol.gif)
), over and over, until they glowed. Now, he can focus his chi into his hands, making them "like unto a thing of iron."
The iron fist can be used in various ways. Sometimes it is exactly what the name implies, making his fists seemingly unbreakable, so he can punch through steel walls or whatever. Sometimes it also packs a bit more, as when he swam to the bottom of a rather large ship and punched it - and the concussive blast was felt throughout the entire ship, which sank in what looked to be minutes. One time, he used it to vaporize a scythe that a foe was swinging at him.
There are also much more unexpected applications. He used it to mend his many broken bones as he lay dying. He burned poison out of his blood. He fought off a blast of radiation, and another time mystical bolts. He even used it to do a Vulcan mind meld once.