What Is It? Extremis was first introduced in the Warren Ellis/Ari Granov comic arc “Iron Man: Extremis” as a creation of Dr. Aldrich Killian and Dr. Maya Hansen. Extremis is a virus that its creators were hoping could replicate the Super Soldier Serum that created Captain America. Sadly, it’s another failed try, and when the virus gets into the wrong hands it becomes incredibly deadly.
How Does It Fit? Iron Man 3’s introduction of Extremis is quite similar to the comics, though it’s more directly an invention of Maya Hansen and more of an incredible medicine than a replication of the Super Soldier Serum. Keeping with the comics, however, is the fact that it causes the titular hero a great deal of grief and heartache.
Who Is He? Aldrich Killian’s history in Marvel comics isn’t exactly what you would call “dense.” Originating in Ellis and Granov’s aforementioned arc “Extremis,” the character is credited as one of the creators of the serum, but doesn’t really live long enough to see its effects. Killian kills himself shortly after his introduction.
How Does He Fit? Killian is played by Guy Pearce in Iron Man 3 and, as you can imagine, has a much larger role than his comic book counterpart. This version of Killian is not only the founder of Advanced Idea Mechanics, a massive tech company that rivals Stark Industry, but also a former associate of Gwyneth Paltrow’s Pepper Potts.