Although director James Cameron had an idea of what he wanted the T-800 to be, it was leading man Arnold Schwarzenegger who shaped Alien’s Xenomorph or Predator’s Predator as one of the subgenre’s most lethal killers.
However, Terminator creator James Cameron did not envision the Terminator as viewers now know him. While Cameron had the original idea for the T-800 while experiencing a fever dream, his vision of a metal exoskeleton emerging from a wall of flames did not provide the helmer with much insight into the Terminator’s disposition. For that, Cameron had to rely on The Terminator's eventual star. Although Cameron originally met with Schwarzenegger to see if the actor was interested in the role of hero Kyle Reese, Arnie’s take on the Terminator was so inspired the director left the meeting wanting to cast the Austrian strongman as the villain.
Initially, Schwarzenegger was not interested in the Terminator role because it had almost no lines, but eventually, he took the part regardless. Arnie’s original T-800 went on to become an icon of sci-fi cinema, and this was due in large part to the advice the actor gave Cameron about the character. Schwarzenegger reasoned that the Terminator should operate like a real-life machine, taking no pleasure or sadistic joy in his killing, but instead coldly completing each mission without any emotional investment. This even included body language, such as the way the T-800 turns its eyes first before the head follows while it scans for targets.
Per a 2019 MensHealth interview, Schwarzenegger recalls telling Cameron, "He's a machine. So everything has to be matter-of-fact… I said there should be no joy, no gratification, no kind of victory lap of any sort." It was clear that Arnie had given more thought into the T-800 than Reese, and his concepts stuck home with the filmmaker. In that same meeting, the actor recalled that "Jim, afterward, says to me, “[expletive deleted], you analyze it better than the way I have written it. Why don't you play the Terminator?’” Interestingly, Schwarzenegger was not the only unexpected big name considered for the role of Reese.
Cameron also offered the part to Terminator: Dark Fate.
