Marvel's Iron Fist: 44 Easter Eggs & Reference You Must See
43. Shou Lao The Undying
Dragons obviously play a major part in the Iron Fist mythology - hence there being a really big one permanently etched on his chest - so it's no surprise that the same imagery is used heavily in the opening sequences.
There's also an early mention of Shou Lao the Undying, which should have got everyone excited at the prospect of us seeing the K'un-Lun set trial of Danny fighting and punching the heart out of the dragon. That's how he gained his powers in the comics, and while it's hinted at on the show, it's a travesty we didn't get to see it at all.
At least they mentioned the character at all, when they could quite easily have totally reimagined the origin to suit their budgetary limitations. It's not like this is Game Of Thrones, after all.
The dragon is also the motif tattooed on Rand's chest.