“It’s kind of like people’s past ghosts coming back,” showrunner Andrea Newman says.

Goodbye, Boden (Eamonn Walker) … hello, Dom (Dermot Mulroney).

Its like Boden raised them, showrunner Andrea Newman says.

CHICAGO FIRE – “A Monster In the Field” Episode 13001

Dermot Mulroney on ‘Chicago Fire’.Peter Gordon/NBC

When a new chief starts, everybodys going to have a different reaction.

And some of the reactions are surprising.

But Boden wont be forgotten.

CHICAGO FIRE – “A Monster In the Field” Episode 13001

‘Chicago Fire’ season 13.Peter Gordon/NBC

Peter Gordon/NBC

And new faces aren’t always a bad thing.

“Bringing new people in is really a joy just as a writer.

“We kept feeling like this is haunted season 13.

It’s kind of like people’s past ghosts coming back,” Newman says.

But Severide isn’t the only one being haunted.

“And Carver is haunted just as a soul.

So we are mining a bunch of that at the beginning of the season.

It will all play out whenChicago Firereturns Wednesday, Sept. 25, on NBC.