"You can't imagine what's coming before we get to the end of this," said Jeph Loeb, head of Marvel's TV division, during a Q&A with reporters on the set of "Marvel's Agents of S.H.I.E.L.D." The show has a lot of big reveals for the last half of the season, beginning with its midseason return on Feb. 4 at 8 p.m. on ABC.

The accelerated pace of storytelling that people expect, now that they're used to binge-watching series in days, not months, has forced the "S.H.I.E.L.D." writers to step up their game. Said Clark Gregg, "I feel like the last 10 episodes are going to have as much story as any 20 episodes of what we had before."

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Yahoo TV spoke with comic writer Korey Hunt, co-creator of "So ... I Survived the Zombie Apocalypse" at Dark Horse, who is intrigued by the recently announced new additions coming to "S.H.I.E.L.D." this season. "I think Bill Paxton is a good addition to the cast," he said, and he believes that Elena Satine has "a great look for Lorelei." However, he isn't sold on the star power of characters they're adding. "They're still playing it supersafe by adding these Marvel Universe characters that practically no one has strong feelings about." Hunt acknowledged that "they can't have Iron Man in every episode," but like a lot of fans, he hopes they find a happy medium soon.

Here's what we know about the comic book characters joining "S.H.I.E.L.D.":

Bill Paxton, who has long been on the wish list of co-creators Jed Whedon and Maurissa Tancharoen, will be permanently joining the cast as John Garrett, the first of three new characters to be introduced from the comic books to the current Marvel television/movie universe.

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Not much is known about John Garrett, even in the comic world. Introduced in the "Elektra" series (by Frank Miller, creator of "The Dark Knight Returns") as an assassin for S.H.I.E.L.D. with a "history of repeat criminal offenses," according to Marvel, he may be a dark influence on the team.

An explosion forces the organization to rebuild Garrett as a cyborg. We don't know whether the character will be introduced as fully human or not; all we know now is that he and Coulson have worked together in the past and will act as a sort of "tough love" version of the team leader.