From mining old comics for new ideas to retelling old tales with new dressings, the rich histories of Marvel and DC Comics have largely shaped their fictional worlds. Even though those stories have filled back-issue bins and defined major characters for decades, they're not set in stone. Over the years, dozens of characters, stories and events have been wiped from comics continuity or been mangled by memory manipulators.

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Now, CBR takes a look at some comic book characters who were actually forgotten. For this list, we'll be looking at characters, worlds and teams that were written out of existence or erased from memory due to psychic manipulation. While some of these characters were originally introduced as forgotten figures, others had lengthy histories that were forgotten by everyone but comic readers.

15 THE FLASH (WALLY WEST)

Wally West flash rebirth

Last year, the long-awaited return of the original Wally West helped launch DC Comics' ongoing Rebirth initiative. Created by John Broome and Carmine Infantino in 1959's "The Flash" #110, Wally West was the original Flash's sidekick, Kid Flash, and a founding member of the Teen Titans. After his mentor Barry Allen died saving the multiverse in 1986's "Crisis on Infinite Earths," West became the Flash and was one of the most prominent DC heroes of a generation.

Even though West was "the fastest man alive," Wally couldn't outrun Barry's legacy. After Allen's resurrection in 2008's "Final Crisis," West took on a diminishing role and was seemingly erased by 2011's New 52 reboot. Although a new Wally West became Kid Flash in 2014, the original Wally West returned in 2016's "DC Universe: Rebirth" #1. While the full story is still unfolding, Wally was seemingly trapped in the extra-dimensional Speed Force and forgotten while a decade of history was erased from the DC Universe. Since his return, Wally has joined the Titans as he's started to put his life back together and solve the mystery of his disappearance.

14 THOR

Thor Tanarus Gabriele Dell’otto

While Jane Foster might wield Thor's hammer Mjolner today, the Odinson wasn't always "The Unworthy Thor." Since his creation in 1962's "Journey Into Mystery" #83, by Stan Lee, Larry Lieber and Jack Kirby, a few different characters have taken some of Thor's spotlight over the years. Although the alien Beta Ray Bill was able to lift Thor's hammer and Eric Masterson briefly served as Thor in the 1990s, neither of those characters erased the Odinson's history.

Thor's longtime adversary Ulik the Troll wasn't so kind. After Thor's death in the 2011 crossover "Fear Itself," Ulik posed as Tanarus and took the Thunder God's place. In a 2011 "Mighty Thor" tale by Matt Fraction and Pasqual Ferry's, Ulik was able to mystically convince the Asgardians and Avengers that he had always been the God of Thunder and had helped form the Avengers. With the help of Loki and the Silver Surfer, Thor was able to escape the limbo of the fallen gods, expose Ulik's deception and reclaim his place in history fairly quickly.

13 1950s AVENGERS

1950s Avengers

In the 1960s, Iron Man, Thor and Hulk helped form the first incarnation of the Avengers. In 1978's "What If?" #9, Roy Thomas and Allan Kupperberg asked "What If the Avengers had fought evil during the 1950s?" In that alternate reality tale, secret agent Jimmy Woo recruited 3-D Man and some characters from the 1940s and 1950s to form a team of proto-Avengers. Although Gorilla-Man, Venus, Marvel Boy and the Human Rocket saved President Dwight Eisenhower from the villain Yellow Claw, the 1950s Avengers quietly disbanded at the president's request.

Until Kurt Busiek, Roger Stern, Carlos Pacheco and Jesus Merino's 1998 miniseries "Avengers Forever," it wasn't clear whether or not that story happened in the Marvel Universe. In that expansive miniseries, the time-traveling villain Immortus revealed that they were from an alternate reality and wiped it from existence with the Forever Crystal. In 2006, Jeff Parker and Leonard Kirk revived the idea of Marvel's 1950s heroes in "Agents of Atlas." With every member of the 1950s team but 3-D Man in that Marvel Universe title, the Agents of Atlas were active in the 1950s and reformed in the modern era.

12 MAXWELL LORD

Maxwell Lord

Created by Keith Giffen, J.M. Dematteis and Kevin Maguire in 1987's "Justice League" #1, Maxwell Lord started out as a far cry from the villain he eventually became. In the light-hearted series "Justice League International," Lord was a sleazy businessman who helped form that incarnation of the team and received telepathic abilities in the 1988 crossover "Invasion!" In 2005's "Countdown to Infinite Crisis," Lord revealed that he had secretly been plotting against DC's heroes and killed his old friend Ted Kord, the Blue Beetle.

Although Wonder Woman snapped Lord's neck on live TV, he was resurrected in the 2010 crossover "Brightest Day." In 2010's "Justice League: Generation Lost," #1, by Judd Winick, Keith Giffen and Aaron Lopresti, Lord used a device to amplify his powers and made most of the world forget he ever existed. Although a few Justice League International members and associates remembered Lord, he convinced everyone else that figures like Bruce Wayne and Lex Luthor had been responsible for his actions.

11 FORGET ME NOT

forgetmenot

While all of the characters on this list have been forgotten in some capacity, ForgetMeNot is the only character with the power to be completely unmemorable. In "X-Men: Legacy" #300, by Mike Carey, Simon Spurrier, Christos Gage and a host of artists, the mutant recounted his unseen history with the X-Men. Although Professor X had to remind himself of the unmemorable mutant's existence, ForgetMeNot helped the team defeat the Brood, moved with them to the island Utopia and gave up a chance to lose his powers.

In 2014, ForgetMeNot joined Simon Spurrier and Rock-he Kim's mind-bending "X-Force." As that series unfolded, psychologically-advanced mutants like Fantomex and Psylocke were able to remember him or deduce his existence through physical clues. Although he was critically injured by a robot from the Yellow Eye agency, the electronic ghost mutant MeMe and Hope Summers healed him back to health. In a rare instance of life imitating superhero comics, ForgetMeNot has been largely forgotten and unseen since 2015.

10 MARTIAN MANHUNTER

Martian Manhunter New 52

Like Wally West, the Martian Manhutner was given a less prominent role in the New 52. After his 1955 debut in "Detective Comics" #255, by Joseph Samachson and Joseph Certa, the Manhunter became a founding member of the Justice League of America. From the late 1980s until DC's 2011 reboot, the Manhunter was a major figure in the DC Universe who regularly served as a major Justice League member.

In the New 52, Martian Manhunter wasn't originally a member of the Justice League. Although it was later revealed that he spent a short time on the team, the Manhunter was originally seen as a member of the covert ops super-group Stormwatch. After starring in "Stormwatch" with several former WildStorm characters like Midnighter, Apollo and Engineer, Manhunter quit the team after 12 issues. Before he left, he used his telepathy to mind-wipe the secretive team, leaving them with no memory of his membership or their adventures. Since then, the Martian Manhunter has been a member of the Justice League America and Justice League United.

9 MON-EL

Mon-El Legion

Even for the most diehard comic book fans, the history of the Legion of Super-Heroes can be headache-inducing. At its core, the Legion is a large group of intergalactic teenage heroes in the 30th century. Thanks to DC's various reboots and time travel shenanigans, the Legion's future has suffered from the ripple effects of present day events. The Superman-esque Legionnaire, Mon-El, was born in the modern era and met Superboy, a young Clark Kent. Created by Robert Bernstein and George Papp in 1961's "Superboy" #89, Lar Gand was put into medical stasis in the Phantom Zone and joined the Legion when a cure was found for his condition.

In 1986, DC's massive reboot "Crisis on Infinite Earths" erased the Clark Kent's Superboy from existence. Accordingly, Mon-El's encounter with Superboy was said to have taken place in a pocket universe that was created by the Time Trapper, a longtime Legion foe. Mon-El eventually killed the Time Trapper and wiped out the pocket dimension, erasing himself from existence with the hope that other heroes would rise in his place. Since then, several other versions of Mon-El have protected the present and far future of the DC Universe.

8 THE NEW MUTANTS

New Mutants Art Adams

In the 1980s, the Beyonder, an ultra-powerful cosmic being, used the Marvel Universe as his plaything. In 1984's "Secret Wars," he forced several heroes and villains to fight each other on the original Battleworld. In 1985's "Secret Wars II," he traveled to Earth to become enlightened and learn about mortality, causing trouble along the way.

The New Mutants, the X-Men's teen team in that era, played a fairly substantial part in "Secret Wars II." After the young teens rejected his offer to make them his disciples, the Beyonder showed up at the Xavier Mansion in 1986's "New Mutants" #37, by Chris Claremont, Mary Wilshire and Bill Sienkiewicz. After a brief confrontation, he killed Cannonball, Wolfsbane and the rest of the team before wiping them from existence. Thanks to how deep her connection with the New Mutant Magik was, only the young X-Man Kitty Pryde remembered they existed. Later that month, the New Mutants were revived as the Beyonder's mindless servants in "Secret Wars II" #9, where they impressively held their own against the rest of Marvel's heroes. Even though they weren't gone for long, this event left major psychological scars on the team.

7 CHRONOS

Walker Gabriel, aka Chronos as seen in DC Comics

Originally, the first Chronos was an Atom villain who committed time-themed crimes. Created by Gardner Fox and Gil Kane in 1962's "The Atom" #3, David Clinton eventually developed a time machine and later gained the superpower to travel through time himself. After his powers became unstable, he effectively died, and his time-travel research was passed on to Walker Gabriel.

As the second Chronos, Gabriel starred in the short-lived 1998 series "Chronos," by John Francis Moore, Paul Guinan, Steve Leialoha and J. H. Williams III. Gabriel started out as a thief, like the first Chronos, before becoming a more heroic character. Near the end of that series, Chronos erased himself from existence in order to save his mother's life. By staying in Chronopolis, a city outside of time, he managed to stay alive for a few more adventures, but he was seemingly killed by the time-traveling villain Per Degaton in 2005. Most recently, he was seen in Limbo during 2008's "Final Crisis."

6 ANGELA

Angela Marvel Guardians of the Galaxy

While she's a resident of the Marvel Universe today, Angela was originally created by Todd McFarlane and Neil Gaiman in 1993's "Spawn" #9. In that Image Comics series, she was an angelic bounty hunter who became a fairly major figure in Spawn's world. After a lengthy legal rights battle, Gaiman was given sole ownership of Angela and sold the character to Marvel Comics.

Angela officially joined the Marvel Universe at the end of 2013's "Age of Ultron" event and joined the Guardians of the Galaxy shortly after. In 2014's secret-revealing storyline "Original Sin," it was revealed that she was Aldrif, the previously unseen and unmentioned sister of Thor and Loki. As an infant, her parents, Odin and Freyja, thought she died in a war between Asgard and the Tenth Realm, Heven. Although Odin exiled the Tenth Realm from the rest of the multiverse, Heven's forgotten angels took in the infant Angela and raised her as their own. After these revelations were brought to light, Angela was cut off from the Tenth Realm and briefly took Hela's place as the Asgardian death goddess.

5 TRIUMPH

Triumph

In 1994, DC attempted to reconcile its various timelines with the crossover "Zero Hour." In "Justice League America" #92, Mark Waid, Brian Augustyn and Howard Porter introduced Triumph, an unseen founding member of the Justice League who had electro-magnetic powers. After being erased from existence on the team's first mission, "Zero Hour" brought him back into the timestream. While his arrogance annoyed DC's other heroes, he joined the Justice League Task Force and starred in his own miniseries.

In 1996's "Justice League Task Force" #37, by Christopher Priest and Ramon Bernado, Triumph lost his soul to the villain Neron in order to gain the lost decade of his life back. While he was reinserted into the timeline, his adventures with the Task Force were erased, and his teammates seemingly forgot him once again. After being tricked into attacking the League, he was turned into an ice sculpture and put in storage, where he was later killed unceremoniously. In 2008, Triumph's son, Jonathan, went on a rampage after being driven mad by his father's ever-changing history.

4 X-MEN: DEADLY GENESIS

The second X-Men team in Deadly Genesis from Marvel Comics

In one of the X-Men's most famous moments, Professor X recruited mutants like Wolverine and Storm to form a new team of X-Men to save the original team from the living island Krakoa. While 1975's "Giant-Size X-Men" #1 showed that successful mission, they weren't Xavier's first choice for a new team. As Ed Brubaker and Trevor Hairsine's 2005 miniseries "X-Men: Deadly Genesis" revealed, there was another X-squad made up of Moira Dr. MacTaggert's mutant students.

These X-Men -- Darwin, Petra, Sway and Vulcan -- were only able to rescue Cyclops before their apparent deaths. Although Xavier made Cyclops forget about his brother Vulcan and the rest of the team, Darwin and Vulcan survived and resurfaced years later, while Vulcan fought the X-Men before taking over the alien Shi'Ar Empire. In the 2009 storyline "War of Kings," he was deposed in a battle with Black Bolt and the Inhumans. Darwin went on to join X-Factor Investigations, and had a moderate role in 2011's "X-Men: First Class," where he was played by Edi Gathegi.

3 EARTH-TWO

Earth Two Justice Society

When DC Comics started rebooting its superheroes in the 1960s, most of its older characters were relegated to the alternate reality Earth-Two. On Earth-Two, DC's superheroes made their debuts in the 1930s and 1940s, formed the Justice Society and fought in World War II. As heroes like Batman and Catwoman married and had kids like Helena Wayne, the Huntress, their continuing adventures were chronicled in titles throughout the 1970s and 1980s.

In 1985, DC tried to simplify its continuity by combing its characters into one main universe with the reality-shattering epic "Crisis on Infinite Earths," by Marv Wolfman and George Perez. While characters like Power Girl, Jay Garrick's Flash and Alan Scott's Green Lantern became part of this new world, other characters, like Wayne's Huntress, were completely erased from existence. Although the 2006 series "52" established a new multiverse and a new Earth-Two, this world was only a copy of the original Earth-Two. Another Earth-Two was created after 2012's New 52 reboot, but this world bore little resemblance to the one lost in "Crisis."

2 SUPERBOY PRIME

DC Comics' Superboy-Prime looking menacing with his eyes glowing red

At the end of "Crisis on Infinite Earths," a few stray characters were sent to live in a "paradise dimension." Along with Earth-Two's Superman and Lois Lane and Earth-Three's heroic Alexander Luthor, one of the multiverse's few survivors was Superboy Prime. Created by Elliot S. Maggin and Curt Swan in 1985's "DC Comics Presents" #87, Superboy Prime was introduced as a young Clark Kent on an Earth where heroes like Superman were fictional characters. After his reality was erased from existence in 1986's "Crisis," he watched the main DC Universe evolve from the paradise dimension, where he was forgotten and unseen.

After punching through the barriers of reality, Superboy Prime returned to the main DC Universe as the primary villain of 2005's "Infinite Crisis," where he tried to destroy the universe. After serving as a major villain for a few years, Superboy Prime returned to his recreated home reality, where his villainous deeds were chronicled as comic books. Ultimately, Superboy Prime was transported back into the main DC Universe and trapped in the Source Wall, a barrier on the edge of reality.

1 SENTRY

Sentry

In 2000, Marvel introduced the Sentry, a Superman-esque hero supposedly created by Stan Lee in the early 1960s. While that story was a fabrication, Paul Jenkins and Jae Lee introduced the Sentry as one of the Marvel Universe's forgotten heroes in the 2000 miniseries "The Sentry." After taking a serum that gave him the power of a million exploding suns, Robert Reynolds became the Sentry, Marvel's Golden Guardian of Good. Eventually, it was revealed that the Sentry had erased all traces of his existence after learning that he and his nemesis, the Void, were parts of the same being.

After his first re-emergence in 2000, the Sentry wiped himself from the world's collective memory once again. In 2005, the Sentry encountered the newly formed New Avengers and accepted an offer to seek help and join the team. Although he still struggled to reconcile the various aspects of his personality, the Sentry served on several Avengers teams over the next few years. In the 2010 crossover "Siege," the Sentry was killed after the Void took over his body. After being revived in 2013, the Sentry, seemingly free of the Void, re-establishing himself as the cosmic protector of humanity.

Stay tuned to CBR for all the latest on Marvel and DC's biggest heroes! Who is your favorite forgotten character? Let us know in the comments... if you can remember them!