He embodied the Joker’s terrifying character

Even director David Ayer admitted that Jared Leto went insane with getting into Joker’s skin:

He constantly has to give birth to himself, he goes away, he comes back, he shoots, he goes away…The Joker is something you have to be, and you can see how exhausting and painful it is for him to be this character. But you can feel it when he comes to work, the crew feels it, everyone feels it. It’s like the birds stop flying. He’s f***ing terrifying.

Did you feel it too?

Leto said:

I have had many challenging roles – but The Joker was challenging in a different way, because of all the expectation and the pressure that came with it. There’s so much great work done. Heath Ledger, Jack Nicholson, Mark Hamill, Cesar Romero – all these people have done such great, powerful work, so there’s a lot of pressure – a responsibility – to deliver something that was adequate and not to let people down.