Having a sibling as an arch-nemesis is the oldest plot in the history books for any superhero. The plot would generally start with the siblings not knowing about each other’s existence or one of them know about the other and it is generally the elder one. The plot generally hovers around the fact that how one sibling was always favored over the other which often leads them to follow different paths and finally crossing paths as superpowered adults with hidden ulterior motives at least for the sibling that has turned over a bad leaf. The epic narrative of the sibling rivalry has been a long ongoing hunt for the best sibling between the two-quarreling siblings dishing out at each other, with one sibling looking for world domination and rubbing the good sibling’s nose in the dirt and the good sibling trying to do what is right and save countless lives in the process along with the lives of the siblings and hoping the sibling will have some sense knocked into his/her brain.
Wonder Woman’s brother
Jason is the twin brother of Diana Prince and the hidden child of Zeus and Queen Hippolyta. Jason and Diana initially got along extremely well, until Jason is revealed to have a girlfriend named Grail, who is Darkseid’s daughter. Somehow Grail manages to hatch a plot and get Jason to do her bidding and eventually slaughter his twin sister Wonder Woman. During the moment of truth, Jason foils Grail’s intention of murdering Diana, but it still hasn’t been revealed which side of the spectrum has Jason switched over to.
In the DC universe, Starfire is often ridiculed for having her original name as Komand’r resembles the name of a popular herb/spice found on earth. However, her sister Blackfire endows the name of Komand’r and is the Queen of the Tamaraneans. Across multiple plots, across the storyline, both of them have generally clashed for the right to the throne and it’s always Blackfire’s maliciousness that has helped have an edge over Starfire.
DC probably tops the list for doing evil siblings the best, and James Gordon Jr. brother of Barbara Jordon aka Batgirl, and the son of commissioner Jim Gordon is no different. James Gordon Jr. is shown to be in psychiatric care early in his life, as he grows, he turns out to be a lot more unstable and a threat to the citizens of Gotham city. In a storyline as James Gordon Jr.’s ill deeds come to light, he is for a short time shown to be brought to justice before escaping the confinement. This is where the battle between the siblings unfolds and Batgirl can injure James Jr.’s eye. He survives the ordeal and is shown joining Task Force X under the name X-Strike.
Doctor Strange‘s brother
Baron Blood aka Victor Strange is the brother of Doctor Strange. He perished years before he was placed in a cryo cold storage by Doctor Strange, only for him to wake up years later with pale white skin and a hunger for blood. The plot witnesses Victor Strange dish out several times to Doctor Strange as he is unable to take accountability for his actions and to stop him from hurting his beloved brother, in an attempt to stop himself Victor stakes himself and has not been known to return since that incident.
Black Panther’s brother
Jakarra is because of an extra-marital love affair between T’Chaka and a spy named Mateena, because of which it kind of gives him kind of a half-ass right to the throne of Wakanda. Jakarra demands it when T’Challa is crowned king of Wakanda which does not go down well with him. In an issue of the story to come to fighting terms with T’Challa, Jakarra stabs himself with vibranium hoping he would be able to get some newfound powers out of it, luckily for him, he does get some powers out of the vibranium turning him into a huge monster with scales. But is still unable to defeat him in hand-to-hand combat.
Batman‘s evil brother
Batman has been around for centuries and has been believed to have multiple evil and villainous siblings, however, the most noticeable one has to be Lincoln March. Lincoln was also one of the candidates contesting for the Mayor of Gotham City but eventually had to be taken out before his accession as Batman found out that he is also a sleeper agent for the ‘Court of Owls’. The DC plot revealed that Lincoln somewhere started believing that he was the younger heir to the Wayne estate and that Thomas Wayne and Martha Wayne were in reality his parents.
Mary Batson is the sister of Billy Batson, even though adopted Mary and Billy have been the sibling crime-fighting duo we all know off. Mary has similar godly powers just like her stepbrother. In a certain issue, however, somehow, she is imbued with the power of Shazam’s old arch-nemesis Black Adam and some start developing a maleficent side similar to Black Adam. But eventually, she gets it under her control and can fend off the evil residing within her.
Nick Fury’s brother
In the earliest issues of Agents of S.H.I.E.L.D, Nick Fury finds himself facing off a villainous evil secret society called the Great Wheel of the Zodiac. Their leader is a mysterious character known as Scorpio, who Nick Fury eventually is shocked to discover is his brother Jacob Fury. Jacob Fury has on multiple occasions appeared in the comic issue to plague Nick Fury under the disguise of Kraken.
Cyclops aka Scott Summers younger brother Vulcan aka Gabriel Summers makes his first appearance in X-Men deadly Genesis #1 (January 2006). Vulcan is the 3rd of the Summers brothers and somehow Professor X knew about him, but still hose to hide the information from his Cyclops and Havok. Vulcan tries to invade earth but is pushed back into space by the X-Men where he ventures into the space building up his fleet of space army, but in a particular encounter with the Black bolt is defeated.
Professor X’s brother
Charles Xavier knew of only one sibling which he remembers removing from existence even before she was born, Cassandra Nova. Cain Marko aka Juggernaut came into the picture much later on and was Charles Xavier’s stepbrother. Cain was not a mutant, but gain his powers of Juggernaut after he came in contact with the Crimson Gem of Cyttorak, making him eventually unstoppable ones he decides to charge in a particular direction. Cain Marko and Charles Xavier have been in an on and off relation from the time they found out about each other, as we witness sometimes Cain fighting alongside X-Men and in some scenarios against them, which draws to only one conclusion that he is not a very headstrong person and that’s what explains the big helmet on his head.