Warren Ellis introduced the Extremis concept to Iron man in a 6-issue story arc starting in January 2005. This arc changed Tony Stark from a cyborg to a posthuman by introducing nanotechnology into his body and altering his physiology to include direct connections with the Iron Man suit. Ellis introduced many concepts and characters that were used in the Iron Man movie trilogy, especially Iron Man 3.

If you're into superhero comics, this is a short arc you don't want to miss. It's available on Marvel Unlimited or through Amazon. In typical comic-book style, it takes some complex scientific breakthroughs and turn them into a magical elixir, yet it brings many of the reasons we research posthuman adaptation into perspective given Stark's need to deal with the story villains. And there are a few great conversations in which characters wax philosophical about their Frankensteinian need to create a future that might be more monster than they would like. My favorite is:

"I like talking about things that'll work. I like talking about genuine outbreaks of the future. Not vacuum cleaner death machines and SATphones no one will buy.

"Why does it have to be consumer goods? Why do we assume the future is only a retail opportunity?"

It's an interesting viewpoint from a Tony Stark presented as depressed over his current role on the world stage. As always with a master storyteller like Ellis, this short series is full of wonderful characters, villains, external and internal conflict and stuff blowing up. Check it out and enjoy.