Marvel Comics and DC Comics have a weird history of copying each other's characters. More often than not, this was just coincidence. After all, neither Marvel or DC can own an entire character archetype or trope. However, some DC characters were so similar to a certain Marvel hero that DC could be rightly accused of plagiarism.
It's difficult to determine if DC's writers, artists, and editors really intended to rip off a Marvel idea, but these specific characters seem to confirm that this was indeed the case. These characters' similarities to certain Marvel's heroes and villains were so glaringly obvious that the only conclusion readers came to was that DC ripped off Marvel.
10 Aquaman Was DC's Namor The Sub-Mariner
It's difficult to determine if Aquaman was DC's first instance of ripping off a Marvel character, but he was definitely one of the first to do so. Aquaman (who debuted in 1941) was literally just Namor the Sub-Mariner (who debuted in 1939) in every possible way. The only real difference was their costume and how they looked.
Aquaman and the sometimes villainous Namor were powerful kings of Atlantis. They fought Nazis in their first issues. Both were integral to their respective universe's hidden histories. Ironically, Aquaman became more popular even if he was a blatant rip-off. Namor only really broke into the mainstream after Black Panther: Wakanda Forever.
9 Guardian Was One Of DC's Many Captain America Clones
Captain America was one of (if not) the most influential superheroes ever created. Before and after he joined Marvel's canon, Captain America was ripped off endlessly by DC and almost every other publisher. Guardian was one of the most prominent imitations, since he was made by Captain America's creators: Joe Simon and Jack Kirby.
Jim Harper was a patriotic superhero who wielded an indestructible shield. Like Captain America, the original Guardian was recontextualized as a World War II-era hero who felt out of time in the modern age. Guardian wasn't the only Captain America rip-off in DC's ranks, but he was notably the one who lasted the longest.
8 General Wade Eiling Fulfilled The Same Purpose As General Thadeus "Thunderbolt" Ross
Gen. "Thunderbolt" Ross is one The Incredible Hulk's most personal enemies. Not only was he partly responsible for turning Bruce Banner into The Hulk, but Ross made it his personal mission to bring Hulk down at any cost. DC's answer to this was Gen. Eiling, who debuted in roughly 20 years after Ross. Eiling was the thorn in Captain Atom's side.
Like Ross, Eiling made up for his lack of superpowers by tormenting a hero born from a disastrous military experiment he oversaw. Things came full circle when Marvel copied Eiling's evolution. In 1999, Eiling famously became the monstrous supervillain The General. Marvel copied this by turning Ross into The Red Hulk in 2008.
7 Gangbuster Was Metropolis' Daredevil
Daredevil wasn't the first urban superhero, but he was the most influential. Instead of saving the world, the at times overrated Daredevil stopped ordinary but still dangerous crimes in Hell's Kitchen. This and the fact that he had a day job as the lawyer Matt Murdock made Daredevil one of the most grounded and relatable heroes ever made.
DC's Daredevil was Gangbuster. By day, Jose Delgado taught in school. At night, he became Gangbuster and fought crime in Metropolis' Suicide Slum. Their similarities included a lack of superpowers, their expertise in fighting, and similar costumes and color schemes. However, Gangbuster never caught on the way Daredevil did.
6 Rocket Red Was The Soviet Union's Iron Man
Rocket Red was one of the most interesting ways that DC ripped off a Marvel hero. In brief, Rocket Red was Iron Man's polar opposite. If Tony Stark Jr. was a narcissist who embodied American capitalism and individualism, Dmitri Pushkin was a friendly team-player and a dedicated Russian patriot. Both were also clear products of the Cold War.
Stark and Pushkin were ordinary heroes who wore power armor. They led groups of fellow armor-users, namely the Iron Legion and the Rocket Red Brigade. Rocket Red never escaped his B-list status, but he still shows up occasionally during DC events. Rocket Red is also more of a legacy name today, whereas Tony is inseparable from Iron Man.
5 Red Hood Followed The Winter Soldier's Footsteps
Bucky Barnes becoming The Winter Soldier was one of comics' most famous and well-received revivals of a Golden Age superhero. As it turns out, Captain America's sidekick wasn't killed in action: he was turned into the deadly assassin known as The Winter Soldier. From there, Bucky went a long redemption arc to atone for his previous villainy.
DC copied this arc almost verbatim when they revived the second Robin, Jason Todd, as The Red Hood. After seemingly being killed by The Joker, Todd came back to life as the murderous vigilante Red Hood. Red Hood was one of DC's most successful rip-offs. He's since become a massively popular anti-hero, not unlike the modern Bucky.
4 Red Tool Was An Affectionate Deadpool Parody
Deadpool starting out as a copy of the popular Deathstroke the Terminator who then evolved into Deathstroke's parody is one of the most famous cases of Marvel ripping DC off. DC seemingly repaid the favor with Red Tool in 2014. Red Tool wasn't DC's first attempt to create its own Deadpool, but he was certainly the most blatant and obvious.
Red Tool was just a color-swapped Deadpool. Like Wade Wilson, Wayne Wilkins was an eccentric and violent anti-hero. Unlike most of DC's bootlegged Marvel characters, there was no pretense to Red Tool ripping off Deadpool. Red Tool was meant to spoof Deadpool from the very beginning, and reader quickly got in on the joke.
3 The Red Lion Was DC's Villainous Black Panther
Shortly before Black Panther hit cinemas in 2018, DC seemingly preempted T'Challa's coming stardom by introducing The Red Lion in 2016. It's not an exaggeration to say that The Red Lion was just the somewhat unsung Black Panther, but painted red. Their backstories and powers were too similar for it to be dismissed as mere coincidence.
Matthew Bland and T'Challa were the undisputed rulers of their respective fictional African countries. They were both otherwise ordinary people who wore power armor that bore the resemblance of a big cat they felt connected to. A key difference was that The Red Lion was a brutal warlord, whereas Black Panther was a heroic king.
2 Damage (Elvis Ethan Avery) Was DC's Incredible Hulk
The Incredible Hulk's conceit was simple yet iconic. Thanks to a military experiment gone wrong, the mild-mannered Bruce Banner became the Gamma-powered Incredible Hulk whenever he lost control of his anger. Because of how dangerous the Hulk was, Banner was depicted as an anti-hero that other Marvel heroes had to be wary of.
Possibly in light of the Hulk's MCU stardom, DC made its own Hulk through the second Damage. Like Banner, Avery was a timid person who became an enraged brute when he was pushed too far. Hulk and Damage weren't just similar; Damage was literally DC's Hulk. To date, Damage is one of DC's most shameless Marvel rip-offs.
1 Sideways Was Just A Blue Ultimate Spider-Man
As far as many fans are concerned, Ultimate Spider-Man was one of Spider-Man's best interpretations yet. Ultimate Spider-Man was fun, relatable, and felt like the perfect teenaged hero for the 2000s. DC apparently agreed with these sentiments, so they ripped off Ultimate Spider-Man wholesale through Sideways in 2018.
Sideways was Derek James: an unpopular kid in school. Derek lived with his adoptive parents, and he had an obvious crush on a close friend who seemed to be out of his league. Sideways' visual similarities to Spider-Man and Derek's parallels with Peter Parker were obvious, but most of these commonalities took notes from the Ultimate run.