"There's a humorous aspect to him, which is something that drew me in from the very first conversation I had with Joss [Whedon]," Spader revealed. "In many ways he's a child, this character, because he's a brand new being who's just come to be. And yet, through artificial intelligence, he has an incredible capacity for knowledge. So he's a very powerful, smart child."
"Ultron takes abrupt turns in scenes," Spader explained. "Red isn't pyschopathic but Ultron is. Yes, he is psychopathic. He's really batsh*t crazy!"