"I gotta tell you, the season that's about to come out, the second half, is our best season since Season One," Reedus told Atlanta's 11Alive during last weekend's Walking Dead-themed Super Bowl party.
"The show's kind of like a virus, it sort of adapts and becomes a different thing. I mean, the secret is, we keep moving. We don't do the same thing over and over."
"We're about to get tested," added Jerry star Cooper Andrews of the series' newest threat, the Whisperers, flesh-clad enemies who disguise themselves as walkers.
"We just saw a group that dresses up in dead skin and we've seen crazy — I mean, I come from a place where the king has a tiger."
Also rejoining the mix in the back eight is Negan (Jeffrey Dean Morgan), who fortuitously won his freedom in November's mid-season finale.
"I think we know that Negan is gonna get out and stretch his legs a little bit," Morgan said when asked for a tease, adding with a grin, "Negan knows more about the Whisperers than you do."
Reedus previously said The Walking Dead weathered the loss of Rick Grimes star Andrew Lincoln — who exited in November but will return to the role with a trilogy of television movies — to become "the best it's ever been."
"We're making the show that we want to make right now and you can feel it on set, you can feel it all over the place," Reedus told Deadline.
"I really feel the scripts and the stories and the episodes are even better in the back eight, I really do. They're f—ing epic, you know, and they're just crushing and they're severe, all of them. The show's morphing into something else but it's got the heart and the feel of the original show, there's just new life breathing through it."
The Walking Dead Season Nine resumes with new episodes Sunday on AMC.