"Iron" is the debut single by Woodkid (real name Yoann Lemoine) taken from his album The Golden Age that was prepared in 2011 but released in 2013. It was written by Yoann Lemoine himself and arrangements by Gustave Rudman. The single was released on March 28, 2011. This song gained immense popularity after being used in a trailer for Assassin's Creed: Revelations. It was also sampled in Kendrick Lamar.'s the spiteful chant in his 2011 album section.80.

A remix EP was also released called Iron (EP) in 2011 charting in its own right.

Iron single (promo)

Iron EP

...
Wikipedia