He worked for FuturePharm with Maya Hansen in Texas, the duo created Extremis, a drug that granted numerous superhuman abilities, and sold some of it to a domestic terrorist cell, which included Mallen. However, Aldrich apparently had a change of heart, and felt guilty about selling the drug. He wrote a suicide note, detailing his feelings and how no one loved him, and then shot himself in his office.
Aldrich Killian was created by Warren Ellis and Adi Granov. His first appearance was in Iron Man #1.
Iron Man 3
Killian was portrayed by English-born Australian actor Guy Pearce in the Marvel Studios movie, Iron Man 3. This version of Aldrich is an amalgamation of Mallen, the Mandarin and Aldrich Killian himself.
In 1999, an unconfident, physically-impaired Aldrich tried to convince Stark about his idea (Extremis) being developed by AIM on New Year's Eve. Stark told him to meet him on the roof, but stood him up and slept with Maya Hansen instead. Contemplating suicide, Aldrich instead decided to split off and work on the project without any outside assistance.
In present day, he became a successful scientist and business man, having created Extremis with Maya Hansen. His physical aliments were completely cured by the drug. However, research was not complete, and in order to further the testing on the drug, Killian hired a man named Trevor Slattery pretend to be the diabolical terrorist and mastermind, the Mandarin. He used the Mandarin's supposed "terrorist acts" to cover up his failures. Killian recruited war veterans to volunteer and become Extremis soldiers, enlisting the help of Coldblood (known by his real name, Eric Savin). He captured Tony Stark and Pepper Potts, converting Pepper into an Extremis enhancile in an attempt to coerce Stark into helping him improve upon the formula and save Pepper. He then attempted to kill the president on live TV, in order to use the Vice-President (who's daughter he promised to save using Extremis) as a puppet leader. However, Tony Stark met him and fought him, using all of his Iron Man suits to destroy Aldrich's Extremis-enhanced soldiers. He then encased Aldrich in his suit and activated the self-destruct mechanism, seemingly killing him. As Tony reunited with Pepper, Aldrich emerged from the fire, heavily damaged, proclaiming himself to be the real Mandarin, and attempted to finish Tony, but was stopped and finally killed by Pepper.
In the movie, he (along with the other enhanciles) exhibits several of Mallen's and Mandarin's abilities, including super-strength, stamina, durability, regeneration, and a certain measure of pyrokinesis, manifesting itself in flame-breath and the ability to superheat any part of his body.