The Shame star, who plays an android named David in the highly-anticipated movie from Ridley Scott, revealed that the character is ambiguous, adding that he could develop human traits as the movie progresses.
"You're essentially trying to build a computer that has a physicality to it, that can respond and understand human behaviour," Fassbender told Collider. "It's programmed to be able to incorporate itself within a human environment.
"So, what happens when you programme that and the programme then starts making its own connections and joins up to its own electrical linking to other areas and forming its own ego, insecurities, jealousy and envy?" he asked.
Fassbender went on to speak about what he found to be most intriguing about the character.
"What I thought was very interesting was that you have this guy who was on his own for two and a half years while everyone else was in cryostasis, so what did he do to amuse himself?" he continued. "The idea that there is something of a little boy there, and that he has to rely on his imagination to keep himself occupied, imagination is a very human trait.
"The way that [screenwriter] Damon [Lindelof] wrote it, people treat him as a robot and there's a bit of contempt towards him because he has all the answers," the actor said. "He's hyper-intelligent. His physicality is more advanced than human beings.
"So, people don't really embrace him," Fassbender explained. "He's sort of used and abused. How does that make him feel, if robots can feel? I didn't want to make a direct, definite choice. I played with the ambiguity. Is this robot starting to develop human personality?"
Lindelof described the process of writing the character of David as "pretty cool".
"I remember a conversation that Ridley and I had, fairly early on, about David," he said. "There was this idea that David is mass-produced. There are 20,000 other David units out there, who look exactly like Michael Fassbender. What a wonderful world that would be, wouldn't it?
"This David, once you take him out of the wrapping, would begin to customize himself. He could change his hairstyle. He could change the way that he speaks. He could have different applications, based on what this unit is designed to do.
"That's where I felt like, as soon as we cast Michael, that's the killer app, right there," he concluded. "It's pretty cool."
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Prometheus is scheduled for release on June 1 in the UK and June 8 in the US.
Watch the international trailer for Prometheus below: