While at PaleyFest, "Legends of Tomorrow" producer Marc Guggenheim said the show would incorporate another DC character -- but not one from the comics or another Arrowverse series. Naturally, that got us thinking about all the possibilities. DC has a long history of adaptations in other media. Characters like Jimmy Olsen, Reneé Montoya and John Diggle came into the comics from radio, animation and TV. Occasionally public-domain characters like Dracula -- or licensed characters like the Shadow and Doc Savage -- interact with DC's super-people; and DC has also integrated "outside" comics characters into its main-line superhero titles.

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Although significantly different interpretations might qualify as "new" characters -- i.e., Debra Winger's Wonder Girl, Halle Berry's Catwoman or the telepathic Dinah Lance from TV's "Birds Of Prey" -- for the most part we won't go that far. Today we'll examine several potential candidates for a spot aboard the Waverider.

15 CHLOE SULLIVAN

Played endearingly by Allison Mack on all 10 seasons of "Smallville" (2001-10), Chloe Sullivan is in many ways the prototype for Arrowverse characters like Felicity Smoak and Winn Schott. Chloe regularly transcended her exposition delivery and plot facilitation functions -- not to mention her shipping possibilities -- and gave the series a necessary emotional core. More capable than the series' version of Lana and a worthy journalistic counterpart to Lois, Chloe was one of "Smallville's" highlights throughout its run.

Writer Nick Spencer and artist R.B. Silva brought Chloe into the comics for their charming "Jimmy Olsen" backup series which started in November 2010's "Action Comics" #893 and finished in May 2011's "Jimmy Olsen" special. In that story, she was torn between her affection for Jimmy and his frustrating man-child tendencies; but it all worked out eventually. At first we think she might be overwhelmed by the outsized personalities aboard the Waverider, but that shouldn't last long. Ultimately, Chloe can put a human face on the Legends' attempts to repair the timeline.

14 THE WONDER TWINS

Love or hate them, Zan and Jayna were introduced to Saturday-morning audiences in the fall of 1977, as part of "Super Friends'" second-season revamp. You know the drill: hailing from the planet Exor, they fist-bump to activate their super-powers. Zan turns into any form of water, while Jayna transforms into any animal. We are both curious and nervous to see how the Legends would receive them. We suspect Zan and Jayna would want to avoid getting too close to any airlocks.

That said, we're not very confident that the Wonder Twins will come aboard for "LOT" Season Three. This is mainly because the hints seem to be for a single character, and of course they're a matched set. (We're not entertaining the idea of bringing along their space-monkey Gleek.) However, that's a minor detail. "LOT" could end up rehabilitating Zan and Jayna from their frequent status as nerd punchlines, maybe by contrasting them with existing Legends. Zan could be the ice version of Steel, while Jayna could transform into an exotic animal Vixen might mimic. Besides, so far the Legends have all been Earthlings; so introducing the Exorian siblings would shake up the team dynamics as well.

13 WENDY AND MARVIN

The Wonder Twins succeeded Wendy Harris and Marvin White, two non-powered "junior Super Friends" who provided viewer-identification characters for "Super Friends'" first season (1973-74). Officially the Justice League was training them to be crimefighters, but really they were there for comic relief, and to make the show kid-friendly. (Since the comics had given the League a teenage groupie in the form of Snapper Carr, this wasn't that unusual.) While Wendy was the responsible one who kept her counterpart on track, Marvin and his canine pal Wonderdog tended to stumble through their adventures, succeeding in spite of themselves.

Nevertheless, thanks to our favorite ex-Time Master, we see a certain ironic similarity to erstwhile "Doctor Who" companions Amy Pond and Rory Williams. We're not saying that Rory is a one-to-one match for Marvin -- and they didn't have a dog -- but if we were running "LOT" that's how we'd try to retool the junior Super Friends. "Arrow" and "Flash" have introduced teenaged heroes already, so "LOT" wouldn't be breaking new ground. After all, by definition they've got superhero potential.

12 BLACK VULCAN

Honestly, we're not sure where the electric-powered Black Vulcan might fit into the Arrowverse. Debuting in 1977 as part of a push to diversify the Super Friends, the need for a Black Lightning substitute came out of a rights dispute with the character's creator Tony Isabella. Of course, now Greg Berlanti and company are developing a "Black Lightning" live-action series which won't be part of the Arrowverse -- so if "LOT" wants to have a Black Lightning-type character, it could once again call on Black Vulcan.

Still, even considering that electric superheroes don't all share the same personality, Black Vulcan would have to be totally different from Black Lightning to justify his addition to "LOT." The character was never that deep to begin with, so the producers would probably be starting with a fairly blank slate. In any event, the team could always use another energy-projector and Black Vulcan's powers could be expanded into electronics-manipulation as well.

11 APACHE CHIEF/MANITOU RAVEN

Joining Black Vulcan at the start of "Super Friends'" 1977-78 season, Apache Chief was a Native American superhero who could grow to giant size -- from 50 feet to continent-straddling. As with many elements specific to "Super Friends," Apache Chief became an Easter egg in the comics and an object of parody otherwise. However, in July 2002's "JLA" #66 writer Joe Kelly and artist Doug Mahnke revamped Apache Chief, sort of, as a Native American mystic named Manitou Raven who eventually joined the Justice League. Manitou Raven died on a mission with the spinoff group Justice League Elite, and his wife Manitou Dawn took his place on that team.

While Apache Chief himself might not be headed to "LOT," we're more optimistic about Manitou Raven and/or Manitou Dawn. They would be good for the group's diversity both in terms of ethnic representation and power sets. With the Hawks, "LOT" has already done a superhero couple separated by death, so that doesn't have to be a big part of Raven and/or Dawn's story. Either one would introduce a magic-user to the team, thereby making magic a bigger part of the Arrowverse as well as contrasting it with the Waverider's temporal mechanics.

10 SAMURAI AND/OR EL DORADO

A Japanese character with wind, fire illusion and invisibility powers, Samurai was the third of 1977's new Super Friends. Mexico's El Dorado came along in 1981, boasting powers of illusion-casting, flight, teleportation, telepathy, and super-strength. Neither Samurai nor El Dorado seem to have gotten a lot of love from the comics themselves, although Samurai (along with Apache Chief and Black Vulcan) received homages on "Justice League Unlimited" and "Young Justice," and a version of El Dorado appeared on "YJ."

As with Black Vulcan, this gives "LOT's" producers the freedom -- if they so choose -- to re-create these characters virtually from the ground up, using the other adaptations' tweaks as appropriate. For example, Samurai's comics counterpart was an actual samurai who received super-powers, and his "JLU" version Wind Dragon was part of a "Super Friends" pastiche called the Ultimen. Basically, "LOT" would be reverse-engineering a character to fit a set of fan expectations, except that with these characters we're not sure what those expectations might be. Since the producers have done more with less (for example, the Bug-Eyed Bandit), we remain optimistic.

9 RIMA THE JUNGLE GIRL

A kind of thematic cousin to Tarzan and Mowgli, Rima was introduced in W.H. Hudson's 1904 novel "Green Mansions: A Romance Of The Tropical Forest." The book is a melancholy tale about man's malignant effects on nature, and its ending certainly doesn't promise more Tarzan-style adventures. Still, "Green Mansions" was adapted for a few different media, including a "Classics Illustrated" comic and a slightly-sunnier 1959 film starring Audrey Hepburn(!).

Naturally, we're most interested in DC's seven-issue "Rima" series drawn by Nestor Redondo (May 1974-May 1975) and her subsequent "Super Friends" appearances in 1977 and 1980. In the comics, she had an affinity for the natural world which bordered on magical; and on "Super Friends" she could summon animals like bears and crocodiles. In the context of "LOT," though, this may sound redundant next to Vixen. While we're reluctant to take too many liberties with an established literary character, we think treating her as Rainforest Aquaman might make her distinct enough. Specifically, while Vixen can mimic the "powers" of different animals, Rima can command them. That could especially come in handy if the Legends find themselves in an unfamiliar wilderness.

8 ISIS

Originally the star of her own Saturday-morning live-action TV series (1975-77), Isis came from the same producers who made the live-action "Shazam!" Played by Joanna Cameron, she was a science teacher named Andrea Thomas who transformed into a superhero via an ancient Egyptian amulet. Isis' impressive list of powers includes flight, super-strength, elemental control, weather control, time manipulation, and intangibility. At the time, DC published a short-lived tie-in comic, but Isis herself wasn't incorporated into the DC Universe until 2006's "52" miniseries. There, she married Black Adam and was later murdered (not by him). Isis also appeared, sort of, on "Smallville," when the goddess' spirit possessed Lois Lane.

Of course, world events pretty much prevent The CW from having a character named "Isis" on one of its superhero shows. That alone practically guarantees that Isis won't be coming to "LOT" anytime soon -- or if she does, she'll have to be another goddess' namesake. However, if the show's producers can get over that hurdle, Andrea Thomas could be a mighty member of the Waverider's crew.

7 HARLEY QUINN

Harley Quinn aiming a gun at the camera

Created by Paul Dini and Bruce Timm and debuting in 1992 on "Batman: The Animated Series," Harley (voiced initially by Arleen Sorkin) has ridden her television popularity into the stratosphere. After a 1999 special issue brought her into the main-line DC Universe, her first ongoing series lasted over three years (2000-03). Harley's second ongoing series started in 2014 and is still going strong; and since 2009 she's also been a regular in "Gotham City Sirens" and "Suicide Squad." Harley's already been on live-action TV, as the manipulative Dr. Quinzel from The WB's "Birds Of Prey," but moviegoers today know her from the "Suicide Squad" movie. As if that weren't enough, "Arrow" teased her very briefly via its own version of the Suicide Squad, she was rumored to be on "Gotham," and a "Gotham City Sirens" movie is planned.

In short, Harley fits all the mystery-character criteria, and would be an undeniable draw of she were on "LOT." Regardless, all that popularity probably means she's not headed to the small screen anytime soon. She's simply gotten too big for the Waverider.

6 THE PROTECTOR

Created by Marv Wolfman and George Pérez, the Protector is secretly Jason Hart, a gifted athlete and detective who acts and sounds -- but definitely doesn't look -- suspiciously like a pre-Nightwing Dick Grayson. When the U.S. government (and some corporate sponsors) asked DC to use the Titans in drug-awareness comics, licensing issues put Dick/Robin off-limits. Because Pérez had already started work on the issues, he redrew the Protector's costume over Robin's. Later stories explained that Dick had trained Jason to lead the Titans temporarily. This he did for three quasi-canonical issues, securing his status as a future Easter egg.

We think this gives the "LOT" producers a golden opportunity to have Generic Nightwing join the team. The Protector comes from outside the proper DC Universe and was designed literally to substitute for Robin when the latter was unavailable. Outside of an ironic appearance on "Gotham" -- something we sadly can't rule out -- we can't imagine any Bat-project wanting him, because within the Bat-family he'd be redundant. Naturally, this makes him perfect "Legends" material, to say nothing of the in-joke possibilities. We look forward to the coincidentally-named Jason telling the Legends about his brother Dick, his brother Tim, his sister Stephanie, etc.

5 THE WARLORD (TRAVIS MORGAN)

Created by Mike Grell and debuting in November 1975's "First Issue Special" #8, Travis Morgan was an Air Force officer who got stranded in the other-dimensional world of Skartaris. Needless to say, Skartaris held many dangers, from sorcery and dinosaurs to the occasional super-science; but Morgan fought them off with his pistol, sword and new friends. Basically "Warlord" was Grell's updated version of a pulpish "lost civilization" saga. It proved pretty durable, spawning a long-running series and a handful of sequel miniseries.

While Travis Morgan has been a part of the DC Universe since "Crisis On Infinite Earths," appearing everywhere from "Green Arrow" to "Convergence," he's on this list because Grell originally wanted to keep him separate. We think Morgan has the skill set and background to be a valuable addition to the Legends. Certainly he has the strategic know-how to give Sara Lance competition for a leadership role, and failing that, he's a master of many weapons. Above all, though, whoever plays Morgan on "LOT" needs to resemble Stephen Amell. While Grell based Morgan's appearance on his own grooming choices, the Warlord and Green Arrow tend to look a lot alike.

4 FRANKENSTEIN

Frankenstein

Everyone knows Frankenstein's Monster was created by Mary Shelley for her 1818 novel. However, his history with DC Comics goes back almost 70 years to May 1948's "Detective Comics" #135, when Batman and Robin traveled back in time to verify that the Frankenstein story was in fact true. Later, the monster (sometimes under Dracula's sway) also fought Superman and the Phantom Stranger. In 2005, Grant Morrison and artist Doug Mahnke revived Frankenstein (as it were) for a "Seven Soldiers" miniseries. This version appeared in "Final Crisis" and a "Flashpoint" miniseries before getting its own New 52 series, "Frankenstein: Agent Of S.H.A.D.E." After that book's cancellation, Frank appeared in the year-long "Futures End" story and was a member of Justice League Dark.

A no-nonsense operative who laments his lack of humanity but doesn't dwell on it, Frankenstein would be a great addition to "LOT." His dry-as-desert personality would contrast well with the more quippy Legends, and the practical teammates would appreciate his all-business approach. Moreover, there's a chance the Legends could run into his ex-wife or his colleagues in the Creature Commandos. He'd probably have a hard time blending into polite society, although we doubt he'd care.

3 BEOWULF

The epic poem of the Geat hero Beowulf is one of the oldest in English literature, dating back to between 700-1000 A.D. In it, Beowulf saves the castle of Danish king Hrothgar by killing both the monster Grendel and Grendel's mother. Later, Beowulf becomes King of the Geats, and dies after dispatching a dragon. This foundational legend has been adapted many times in many media, including a DC comic which ran six issues (April-May 1975 to February-March 1976); and was written by Michael Uslan and drawn mostly by Ricardo Villamonte. More recently, Beowulf guest-starred in "Wonder Woman" issues #20-23 (July-October 2008), and a post-apocalyptic version appeared in the New 52 "Sword Of Sorcery" anthology.

Besides the many films, books and even operas featuring Beowulf, the character has guest-starred on "Xena," "Star Trek: Voyager" and "Once Upon A Time" -- putting a "LOT" stint definitely within the realm of possibility. We're not sure how well Beowulf would do aboard the Waverider, but you never know. Once he gets over the future shock and language barrier, Beowulf could be the monster-slayer the Legends never knew they needed.

2 ZETA

Zeta-Project-Banner

Created by Robert Goodman and voiced by Diedrich Bader, Zeta is an assassin droid who went on the run after realizing one of his targets was innocent. He's super-strong, can disguise himself holographically and comes with an R2-D2-esque array of tools and basic weapons. Since Zeta first appeared on a 2000 episode of "Batman Beyond," his exploits occur in the DC Animated Universe's future. This probably makes him one of the few characters from the DCAU to qualify realistically for this list, since Terry McGinniss and his colleagues are no doubt either part of an off-limits rights package or come otherwise from the comics.

We think there's a decent chance of Zeta appearing on "LOT." His "Batman Beyond" connection gives him a natural fit within that possible DC future, as well as an awareness of superheroes, generally. Although his natural form would likely be C.G.I., his holo-disguise could get around that easily (and conveniently). Besides, there's always room for a cybernetic being who's learning how to be more human. A Zeta/Gideon romance is probably out of the question, though.

1 HUNTRESS (HELENA KYLE)

While Helena Kyle's Huntress (played by Ashley Scott on 2002's "Birds Of Prey" TV show) seems somewhat similar to Patience Price from 2003's "Catwoman," after much reflection Helena is different enough to make this list. Like Helena Wayne, her parents are Batman and the late Catwoman; but in the TV-"BOP" continuity, Selina Kyle never married and Bruce Wayne didn't raise her. Moreover, for some reason Helena has feline-style abilities including super(ish)-strength and agility. They're not quite the same as the full-on cat-powers of "Catwoman" '03, but they still distinguish her from Helena Wayne's bat-influenced schtick -- not to mention Helena Bertinelli's mob ties, religious background and teaching career. Additionally, because the "BOP" series didn't really do superhero costumes, Helena mostly wore a cape-like coat.

Since "Arrow" already introduced the Helena Bertinelli Huntress, why would it bother with Helena Kyle? Well, she's a fierce fighter with a strong independent streak who (thanks to rights issues) probably can't claim either parent's costumed legacy. Still, that might be turned into a quest for her mysterious parents, or something similar. Additionally, if White Canary became Huntress' mentor, it would invert the relationship between TV-"BOP's" Huntress and the teenaged telepath Dinah Lance.

Who do you think is "Legends of Tomorrow's" mystery character? Let us know in the comments!