The creator went on to speak out about the team’s research of the disease, and how this made Ivar act the way he did.
He added: “We talked to some people whose relatives has brittle bone disease and what came out of that was that they are angry a lot of the time. It’s a horrible predicament to be in, a horrible disease.
“And so, [even with] the idea of Ivar lashing out and doing bad things, I never lost total sympathy for him because I understood his condition. I understood his psychology.”
However, Hirst revealed he plans to pull Ivar out of this “dark side” next season.
source: express.co.uk