‘The Walking Dead’: New Season 9B Cast Members

The Walking Dead in its second half of Season Nine is set to introduce series newcomers Samantha Morton, Ryan Hurst and Cassady McClincy as members belonging to villainous enemy group the Whisperers.

Introduced in Sunday's mid-season premiere return are Whisperer leader Alpha (Morton) and daughter Lydia (McClincy), ahead of the arrival of Alpha's vicious number-two Beta (Hurst).

Season Nine will immediately unravel what lies behind the fleshy masks of its newest foes, who showrunner Angela Kang calls a "scary group."

"We really start delving into and showing what the Whisperers' philosophy is when we get back into the new season and they are unlike any group that we've encountered before, just their philosophy to survival is very specific," Kang told ComicBook.com, adding she's "really excited" about new additions Morton and Hurst.

"I just think they brought so much energy and intensity already to the process, like in such a great way. And I think we get to tell a bit of a story that is sort of a mystery. I think in many ways they're the most formidable group that we've come across because they have the power of zombies behind them. So that's something that I'm really excited for people to see."

As the cruel and unforgiving leader of the Whisperers, Alpha brings with her a menacing presence that permeates throughout The Walking Dead — on screen and off.

"When [Morton] goes into character you just want to leave. You want to run away as fast as you can and as far away as you can," Magna actress Nadia Hilker previously told Express.

"There's something about her, there's a button. She just becomes a very different person and her energy — you feel like you can't breathe and that's very powerful."

Following the departures of Rick Grimes (Andrew Lincoln) and Maggie Rhee (Lauren Cohan) earlier this season — both characters had significant confrontations with Alpha in the comic books — Daryl Dixon (Norman Reedus) will be at the forefront of the clash with these new foes, who disguise themselves within the skinned flesh of walkers.

"There's a lot of Daryl and Alpha stuff coming up. They're coming from two different places. She's coming from a place of she's got it figured out," Reedus said, teasing a "mutual respect" will emerge between Daryl and Alpha.

The Walking Dead Season Nine debuts new episodes Sundays at 9/8c on AMC.