"The Walking Dead" fans weren't disappointed during this year's Comic-Con International in San Diego, as a brand new trailer for the anticipated fifth season of the AMC drama debuted during the convention, chock-full of possible spoilers of things to come -- but according to series creator Robert Kirkman, the trailer really only scratches the surface of Season 5, despite how meaty it was.

"There's so much going on [in Season 5], that the things we've given away are really just the tip of the iceberg," Kirkman told reporters at Comic-Con. "So, it doesn't really matter that you've seen Rick with Judith or some of the other things that you might catch here or there inside that trailer, just because there's so much going on under the surface to be revealed, that people are still going to be very surprised. If you think you know what's going on from watching that trailer, you might not. There are a lot of twists and turns along the way."

A generous amount of story and character development is par for the course on "The Walking Dead," but it certainly presents a challenge for Scott Gimple, about to enter his second season as showrunner following a critically acclaimed debut in Season 4 -- but it's not necessarily the amount of content that he's worried about.

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"The number one challenge with this show is time," Gimple said. "The time in the day we have to make the show, the time that we have to do the scripts, the time that we have to do the edits and all the juggling. There's such a support team, such a professional show, such great people. It's not easy, but I'm very, very, very lucky to be doing it. I just remember that every day. Ultimately, the challenge is doing work at as high a level we've done before, or higher and pushing ourselves and pushing ourselves and pushing ourselves. I love doing the premieres with Greg because we're the kings of self-inflicted neuroses. It's like dueling neuroses. It's pretty awesome."

Executive producer Greg Nicotero directed the Season 5 premiere, and said that one of his main goals for the new season -- much like Season 4 -- is to ensure that viewers still see the walkers as a danger to the survivors.

"After Season 3, one of my concerns was making sure the walkers still were a relevant threat," Nicotero said. "If you have a monster and you take the teeth out, it doesn't serve much of a purpose any more. A direct result of that was the big spot scene, where the zombies are coming through the ceiling. It was an idea that Scott came up with after we had that conversation -- 'Wow, isn't it cool that you can take our people who are trained survivalists, but put them in a situation that they couldn't possibly be prepared for.' We've done some stuff this season that far exceeds even the burned walkers and the crispy critters and the well walker and the moss walker. I feel like those are the appetizers to some of the stuff we've done."

"There's crazy walkers this season," agreed Norman Reedus. "We just did some stuff that was insane. I'm constantly blown away by this team."

Reedus' Daryl Dixon, one of the few characters on the television series not introduced in the comics, said the evolution of his character has been "a gradual change from season one," influenced by the writing and the performances of his fellow cast members.

"All the things that build up and that you do, all the things that affect you, the situations around you, the other actors -- I think mid-four to now is different than mid-three to four," Reedus said. "It's constantly changing. [Beth] was the little bright light at the end of the tunnel, and I was getting closer and closer until someone blew it up. You're constantly changing."

Indeed, Daryl's arc during Season 4 as he and Beth, played by Emily Kinney, journeyed together proved to be a popular one amongst fans -- and Kinney said the fourth season was a good opportunity for audiences to see both characters in a new light.

"It was a chance for the audience to get to know both of us in a different way," Kinney said. "We had so many scenes where we were talking about ourselves and our past. It was a chance for these two characters who weren't in any scenes together to connect. While we connected, you got to know Beth a little bit better. I know I as an actor got to know Beth a little bit better. She hadn't had some of those more revealing moments before. It was very satisfying. I think the purpose that it served was to get to know us in a different way.

"I definitely think Beth's ready for whatever's going to come at her this season," Kinney continued later. "It's been a little sad, I've been separated from them, so I haven't gotten to see friends and co-workers as much, but it's been really fun."

Daryl and Beth weren't the only characters splintered off from the main group -- Rick, Carl and Michonne become somewhat of a family following the destruction of the prison, and actor Andrew Lincoln stated that the upcoming season will see "a more complete Rick" than in seasons past.

"I think it's somebody that has no doubt that the brutality and the humanity within him are just as valid," Lincoln said. "There's no conflict anymore. He's incredibly pragmatic, he's very uncompromising, and as a result, an incredibly formidable leader. That doesn't mean he's not a great father, and has moments of tenderness -- I think he's accepted that both of those things are just as important. What's the point of fighting unless you have those moments. I think from what we've shot ... the whole nature of family and unity -- if you stand beside Rick, you're family. If you stand in front of him, you're a problem. I think that maybe the themes within this season are about that within the group and without the group.

"Why are we still alive? What is it about our group? Why are we so successful? I think it's because it is a true democracy," Lincoln continued. "Rick listens to people. He goes, 'This is the way I think it should be done,' but if someone has a better idea or someone is more qualified, he'll go, 'Yeah, okay. Let's do that.' ... We carry the future. That makes us incredibly strong."

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Chandler Riggs, who plays Carl, said that audiences should expect to see the growing boy follow his father's lead as the series progresses, and discussed the evolution of his character since the first season.

"He's learned to respect Rick fully," Riggs said. "And really being able to see what he's going for that Carl actually really does need Rick to survive. The really interesting arc of Carl's character is that you see at the end of Season 3, he just shoots a kid in cold blood and he said, 'I had to do it.' At the end of Season 4, he realizes what he's done. 'I'm a monster for doing this,' which means he's able to do the things that he has to do, but he's conscious of what he's doing at the same time, which a lot of characters don't have."

Completing the trifecta of characters is Danai Gurira as Michonne, who said that the new family unit may bring out an even more ferocious side of the character, especially considering she's opened up a bit and has something significant to protect.

"I think that if you have people to protect, you can actually become more ferocious, like a lioness," Gurira said. "My sister and I were really stupid -- we were on a safari in December in Zimbabwe. She took all these pictures because we found all these lionesses with the lions. They would make the little lion cubs go away, because they were trying to figure out what we were. They were watching us and watching us -- just chilling, and we thought they were so far away. She took pictures and blew them up later, and there were three other lionesses we couldn't see that were ready to pounce at any second, watching us watch their kids. ... When you have something to protect, I used to say she was like a cat, but now I think she's more like a lioness because she really cares about things she doesn't want to see harmed. She will go possibly further to protect them than she would have done before."

In many ways, the evolution of character and gradual payoff is one of the major reasons why Season 4 proved to be so popular amongst fans. According to Nicotero, the seeds for the entire season arc were planted very early on, and even extend into the fifth season in a big way.

"You never know what's going to blossom, how it's going to grow," Nicotero said. "Last season, we started at the prison and we were laying down all these little -- can you come back from the things that you've done -- and seeing Clara and the Governor's journey. It really is very thoughtfully choreographed. Where we are at Season 5, we're almost at the mid-season. So, all those little plants -- everything's blooming and blossoming. You invest in this storyline and suddenly it's gone and the story takes another turn. Scott is tremendously thoughtful on how he propels his characters forward -- but there's nothing that's written in anything in Season 4 that didn't pay off. Every little thing that he planted paid off, with Lizzie taking the heads off the rats -- we built that mystery. All that stuff pays off so that by the time we get to the end of the season, you're blasting towards this finale because you recognize all the little plans that have been planted through the entire course of the season."

Meanwhile, Melissa McBride's Carol is still out there, and there are certainly plans for her in Season 5 -- but whether she reunites with the group is still up for debate.

"The way that the world is really changes everyone's world-view," McBride said. "From where they were, each event that happens, each turning point in their life in their apocalypse, I think it shifts their world-view a little, certainly. Everybody is looking at everybody going, 'Does my world-view mesh with yours? Are we on the same page? What is this?' Are they going to accept her? Are they going to understand what happened? Are they going to be angry? I don't know."

That said, there are certainly still a few characters that haven't gotten as much screen time as others due to their recent addition to the cast -- both Tyreese and Abraham were introduced over the course of Season 4, meaning there's still a lot more to explore for both characters.

"He's trying to make a stand, to a certain degree, in his beliefs and his ideology about not participating in any kind of -- what he feels is -- unnecessary violence, or trying to be diplomatic or trying to maintain humanity and have that affect on others around [him]," Chad Coleman said of Tyreese. "But it's a push and pull. It's like a tug of war with him as far as that's concerned. It feels like whereas he was searching for it before, it feels like he might be standing -- being sure about what it is he believes, and being sure that it's the right thing to do. We may be delving more into him having a strong stance, if you will, but it's still who's across from him and what they're flinging at him and what he's slinging back. It's tough, this dude has a huge heart, and it's about trying to hold onto it."

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"I think one of the things, as a fan of the show, that I've loved that Scott has brought to it is the fact that we get deeper with all the characters," Michael Cudlitz said. "I always feel like it's so important to empathize and sympathize with all these people so you know what they're going through, even people who you love to hate every week, you need to know what's driving them to fully hate them -- or fully love them."

Speaking of love, Maggie and Glenn were separated over the course of Season 4, and the trailer makes it seems as though their reunion won't be much of a quiet moment. Lauren Cohan said that part of Maggie's motivation for trying to find Glenn is the hope that Beth might be with him.

"I think that Glenn along the line has been established as this watcher and caretaker of a lot of people," Cohan said. "He was taking the more dangerous missions for the good of the group and I think that what we'd hoped the audience would understand that if she finds him, that he would be with her and he would somehow be protecting everybody that had been lost when we ran out of the prison, and definitely that it's -- you'll see this year."

Steven Yeun is one of a select few actors that has been with the show since its earliest episodes -- and as such, he agreed that his character has "changed quite a bit."

"I think his heart's remained true, that through line is always going to be there. He's more been unlocked," Yeun said of Glenn. "The second season, Maggie says, 'You're pretty dumb for a smart guy.' That's very accurate. He had no idea of his potential. As he gains respect in the group, as he gains respect for himself, he starts to assert that. I always thought this and I hope I'm not wrong, but Glenn is the sum of all the people. You hear the adage that you are the sum of the five people closest to you, and I feel like there are so many people that have touched Glenn, influenced Glenn, to become the person that he is. You think about all the conversations he must have had with Dale that were never onscreen, all the conversations he had with Herschel that were never onscreen and even the ones onscreen, the moments I'm sure he shared with Maggie, looking at Rick as a leader -- he's just feeding off all these people to become the person he is to this point. It is very strange to think back as an actor to say, 'Wow, it has been five seasons.' It's been a long time, but I've really been lucky to have been written a character in the long-form as it has. It's been a really long arc, but a very gradual and effective one in my opinion. We didn't jump the gun too soon."

"It's actually a very slow burn with Glenn," Gimple said, responding to Yeun. "It's interesting -- I'd never heard that adage before, but I really like it. As far as this show, this season with all these people together, wherever they may be, there's an escalation and de-escalation of these characters onscreen. There's a little bit of 'Rosencrantz and Guildenstern Are Dead.' Sometimes these guys are Hamlet and sometimes they're Rosencrantz and Guildenstern. Yet, we take -- and I've been working with all the writers on this -- if there's one line or two lines, we use that towards the overall story. With Maggie in episode two, it is two visual beats that have to do with her overall story. It's an incredible dance of these characters' evolutions as each one of them is evolving."

However, with "The Walking Dead," the key word is always "change," and while Kirkman couldn't state exactly what kind of changes amongst the cast may be coming, he did say there were definitely some in store -- whether it's new additions to the series or some characters getting taken off the table.

"There's always going to be new blood coming into the show, new characters being brought in," said Kirkman. "It's definitely going to be a guessing game. We always try to change things up, have some guest characters come in, and others that will stick around. I think Tara's a good example of that. We're always going to be changing things up and putting new people in. Our cast is continuously changing, unfortunate as that can be sometimes. It's just the nature of what we do. I wouldn't expect Season 5 to be any different."

"The Walking Dead" Season 5 premieres October 12 on AMC.