Ciaran Hinds did a little chatting at BBC’s Michael Ball Show, and talked about the Steppenwolf process in Justice League. He never wore a costume, silly.
I’m sorry I’m not in costume. I didn’t even have a costume when I was doing it. It’s all done in motion capture. So… they stick a helmet on your head, they put two cameras around, and they capture all your expressions, facial expressions. So basically, they’re going to concoct some kind of construction and they will use my facial expressions – eyes, mouth, voice – they’ll turn into this murderous, avenging Steppenwolf from the planet Apokolips, apparently. Who’s bent on Hell on Earth.
He also says that the Cast didn’t meet him.
No, I don’t know whether they’re all afraid to come and meet me– no, no they weren’t, really. Because it’s imaginary, you do it with green screen… That was another challenge, you could say, yeah. But it was quite fun. And they’re very encouraging in what you do, suggesting ‘Over here, look over there, imagine that, do this here, they’re coming at you now.