The showrunner described the zombie drama's next run as "very adrenalised" and "very much a human drama" in an official AMC interview.
"All these horrible things are being thrown at our characters at such a relentless pace that the audience won't be able to catch their breath and figure out what's going on," he explained. "So I think it's just the idea that you are immersed in this apocalypse, and there really is no escape."
In the show's season two finale, Rick (Andrew Lincoln) took charge of his fellow survivors, with fans nicknaming his new ruthless reign a "Ricktatorship".
"Rick's reign is initially successful in the fact that they do discover this prison and that proves at first that Rick was right - that there's a place out there that perhaps they can be safe," Mazzara revealed.
"The question becomes, how far can he push the group? What is the breaking point? And Rick will certainly have to deal with how far can he push himself and what is his breaking point."
English actor David Morrissey will also debut in The Walking Dead's third season as the villainous Governor, a fan-favourite character from the original comics.
"Part of the attraction of The Walking Dead for our fans is that it feels real, and that means that the Governor has to feel real," Mazzara suggested. "He needs to be a person who has a real soul and has a depth and intelligence, and he's not just a cardboard arch-villain who's going to play as a foil to our characters.
"I think David Morrissey is doing a phenomenal job finding the humanity in that character and by having that humanity so prevalent when he commits atrocious acts, I think they'll be that much more horrifying."
The Walking Dead airs on FX in the UK and on AMC in the US.