“The Walking Dead” lost a few familiar faces in the first half of Season 5, but fresh blood will be introduced when the AMC series returns in February. Entertainment Weekly is reporting that Ross Marquand, whose TV credits include “Mad Men” and “Phineas and Ferb,” will join the zombie-centric show for the final episodes of the fifth season.

While Marquand’s casting was announced, his character information was not. But that hasn’t stopped fans from theorizing about the new role. Since “The Walking Dead” is based on Robert Kirkman’s comic book series of the same name, some are scanning the pages for clues. Both EW and TV Line are speculating that Marquand could be taking on the role of graphic novel character Aaron.

Who is Aaron? The character made his first appearance in Kirkman’s comic books in issue 67, which was released in November 2009. The issue found Rick’s group just outside of Washington, D.C., their destination because of Eugene’s supposed knowledge on how the zombie virus spread. Eugene had managed to trick everyone into believing he was a government scientist when he was really just a high school science teacher. His secret was revealed after a scuffle with Rick exposed that his special government radio lacked a battery. Abraham attacked Eugene, upset that their journey had been for nothing. Even with the setback, the survivors decided to continue to Washington in hopes of getting food. But before they could go any further, they were approached by a stranger named Aaron.

Aaron came from the Alexandria Safe-Zone and was one of their “recruiters,” along with his boyfriend, Eric. His job required him to search for other survivors and see if they should be invited to join their haven. Aaron approached Rick’s group, but he wasn’t greeted with open arms. Hesitant to trust anyone after the Governor-Woodbury fiasco, Rick tied Aaron up until they could figure out if he was a good guy or not. In the end, Aaron won their trust and Rick’s group joined the Alexandria Safe-Zone survivors.

As “Walking Dead” fans know, the AMC series doesn’t exactly follow the comic books. At the end of the midseason finale, Eugene’s secret was exposed and the group was left without a haven or place to go. If the show is to follow Kirkman’s graphic novels, the Alexandria Safe-Zone – and Aaron – could be featured in the second half of Season 5.

It’s also important to note that Kirkman and executive producer Scott Gimple have discussed the introduction of a gay character in interviews and during “The Talking Dead” midseason finale.

“I wouldn’t say anything more than that,” Gimple teased fans in December of the new role. “I’ll just say that in the comic there is more than one gay character, so it may be the one you are thinking of or it may be another one.”

“The Walking Dead” returns to AMC on Sunday, Feb. 8, at 9 p.m. EST.