The newest addition to ABC's Castle does not play by the rules.

'Castle's Next Season Will Feature A 'Firefly' Reunion

New character Hayley (Toks Olagundoye), a security specialist who joins the precinct in season 8, will provide an interesting dynamic to the team.

Castle co-showrunner Alexi Hawley spoke with Entertainment Weekly about what Hayley will bring to the table in season 8.

Will Martha Rodgers Still Be In Castle's Life In Next Season of 'Castle'?

"[Toks] plays a really dynamic, fun character," he said. "It's a voice that the show doesn't have. What's great about her is Castle [Nathan Fillion] has been investigating cases police-adjacent, so it's always about doing things the way police would. She doesn't do things that way, so that fun dynamic of, 'No, we break in rather than get a warrant,' is kind of fun."

And while Hayley won't be quite as extreme as Ethan Slaughter (Adam Baldwin), who is returning in season 8, she still provides a different dynamic.

"She's a little easier than Adam Baldwin [was] on him, but there's definitely an energy about her which is a lot of fun," Hawley said.

Additionally, Hayley will become like a big sister to Alexis (Molly Quinn).

"We like the idea of her as a mentor to Alexis in a way that Beckett [Stana Katic] has been, but because she's also Castle's wife, ultimately Hayley can play a little bit more of an older sister," Hawley said. "This season is really about growing Molly up. She's been playing the child for seven seasons and now she's 21 years old. She's a grown up. This year, she's going to be more sophisticated. That relationship with her father will change because she's not a little girl anymore."

Castle season 8 premieres Monday, Sept. 21 at 10 p.m. ET/PT on ABC.

Tags: Castle television ABC