Extremis was developed by Aldrich Killian and Maya Hansen in an attempt to recreate the Super Soldier Serum. Extremis rewrites the operating system of the human body, upgrading strength, speed and durability to the very zenith of human possibility.The Extremis virus, when injected into living tissue, results in a wide range of effects within the host organism. The intention of Extremis was to enhance, although the compound was flawed. In all hosts, it causes intense pain until it either bonds with the host successfully, or destroys the host in a violent explosion. The Extremis virus completely healed Killian's body of his disabilities, much like the Super Soldier Serum did with the frail and sickly Steve Rogers. Extremis enhances the body, upgrading strength, speed and durability to superhuman levels. Killian was shown to have the most advanced capabilities through his infusion with Extremis. Killian also seemed to have some skill in martial arts, as he was able to effectively fight Tony in hand-to-hand combat in correlation with his Extremis abilities.
Extremis Abilities
Healing Factor: The Extremis virus imparts incredible restorative capabilities upon the host organism, which was its primary original intention. Superficial wounds close over and heal completely in a matter of seconds, and severed limbs can take minutes to regrow.
Superhuman Strength: The Extremis virus enhances the muscular power of the host considerably. The extent appears to vary within marginal limits, but most have demonstrated the ability to hoist the weight of a human male effortlessly in one hand and hurl such a weight across a room.
Enhanced Agility: The Extremis virus enhances musculature to become more powerful in its motion, granting the host marginally enhanced agility.
Enhanced Healing : Extremis gives the human body tissue regeneration capabilities. Killian was able to regenerate his left hand after Tony had cut it off during their fight with Tony wearing the Silver Centurion armor. Despite Tony managing to trap Killian with the Mark XLII and causing it to self-destruct, a weakened Killian still managed to rise from the resulting wreckage.
Exothermic Manipulation : Extremis granted the host the ability to consciously raise the temperature of parts of his body, allowing him to control the extent that it might only scorch skin, or increased to the point where it can cause steel to turn into a molten state. Killian was able to heat the Iron Patriot armor to the point of forcing it to auto-eject Rhodey. Killian was also able to melt through the Silver Centurion armor with ease forcing Tony to auto-eject out of the damaged armor. Killian's ability to generate heat in correlation with his enhanced strength also allowed him to punch, cut and tear through many of Tony's Iron Man suits.
Fire Breath : The ability to eject a stream of fire from the mouth akin to a dragon, seemed to be unique to Killian, as none of the other Extremis enhanced superhumans demonstrated such power/control.
An unfortunate side-effect is that if someone takes too much Extremis, or their body rejects it, they will explode in a blast of heat measuring 3000 degrees Celsius, vaporizing anyone around them.
