For the characters of The Walking Dead, there is plenty of mystery surrounding the introduction of Aaron, the man who seemingly appeared out of nowhere at the end of the most recent episode.

Turns out, the same was true for actor Ross Marquand in real life. "They gave me a very brief description of the character, enough to clue me in on some things that would help in the audition. But ultimately, I didn't know [who I was playing] until I booked the part," Marquand tells TVGuide.com. "I was just over the moon when I found out who this character was. He's such a fantastically layered character."

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As readers of the comic books the AMC series is based upon know, Aaron is a recruiter for a group of people from a community known as the Alexandria Safe-Zone. "[Executive producer] Scott Gimple basically said, 'I want you to look at the comic books and derive as much useful information as you can from that, but ultimately I want you to make this your own and take this character where you think it should believably go,'" Marquand says. "That was a really wonderful gift to receive from him, because there's so much pressure to satiate the fan base. I wanted to make sure I honored that."

So, just who is Aaron in the TV version? "He's an affable man. He's very nice, he's very polite, and he's almost Boy Scout-like in that regard," Marquand says. "But there's also this sort of wisecracking side that I think is really disarming and quite charming in this environment. He's approaching people that have been on the road for very close to two years now and they've been through the ringer."

Indeed, on Sunday's episode (9/8c) Aaron will have his work cut out for him as he tries to charm Rick (Andrew Lincoln) and his group and convince them to join the folks at Alexandria. After all, recent safe havens such as Woodbury and Terminus have been anything but. "Aaron is keenly aware of how difficult this is going to be," Marquand says. "It's going to be the hard sell of taking this group from the emotional, extremely wrought place they're at. [They're] coming off of not only losing some of their most beloved members, but they've also just come off of days and days of heat exhaustion and no water. He's meeting a group of people that are completely at wit's end, and he needs to really win them over."

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However, Marquand suggests that he isn't simply visiting Rick & Co. to woo them. "As much as Rick and the rest of the group are sizing Aaron up, he is doing exactly that to them," he says. "He's gotten to know them from what little he's seen of them. [Aaron believes] they must be a pretty decent group if they're traveling with kids. But they've also demonstrated a great deal of violence. When you take people who have been out in the world for that long, [who are] really going back to a more animalistic side of themselves, you're going to meet some serious aggression. So, ultimately, he's sizing up them and deciding is this a group that he can trust in the community that he wants to introduce them to."

But can Aaron himself truly be trusted? Or is he just the next Governor or Gareth? "I will allow the audience to make up their mind," Marquand says. "I would be extraordinarily suspicious of Aaron, for no other reasoning than the history of the show. Every other extremely disarming nice person on the show has tried to ultimately kill them or control them in some way, shape, or form. However, I think people will believe what they want to believe and so they'll learn a lot more about him and his relationship to the group in the next few episodes.

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"How do you put your faith in someone who is so completely outside of the realm of what they are used to?" Marquand continues. "Aaron stumbles out of the woods dressed like he's coming out of an L.L.Bean catalog and looks so sweet and so dapper and so clean-cut. Any other person in a normal setting would say 'Oh, he looks like a nice guy.' But in this particular scenario, you have to acknowledge the fact that everyone is suspect. Everyone is open to interpretation."

The Walking Dead airs Sundays at 9/8c on AMC.

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