Black Widow is one of the greatest spies of the Marvel Universe. The Russian agent (whose real name is Natasha Romanova) was trained as a child in the infamous Red Room, where she learned the craft work needed for a career in espionage and assassination. She killed her first target while not yet in her teens, then later defected to the US where she joined the Avengers.
As Black Widow can infiltrate any environment and blend in, an interesting thought experiment is to consider how she would react if dropped in the middle of the DC Universe. As a bit of a black hat operative, it seems likely she would begin by scoping out DC's villains. These are five DC villains Black Widow would get along with and five she'd hate.
10 Get Along: KGBeast
Like many Russian characters, KGBeast has the misfortune of being stuck with a moniker created when the Soviet Union was not a distant memory but a political reality. This character's real name is Anatoly Knyazev and he is an world-class assassin trained by the Russian government.
As both Black Widow and KGBeast are elite government agents groomed to kill, they have a lot in common. More than that, there are just some comforts that come from sharing a language and culture with someone, which would give them plenty to bond over.
9 Hate: Harley Quinn
While Harley Quinn is more of an anti-heroine these days, she was introduced to fans as a villain and many people still think of her as the Joker's girlfriend and favorite henchwoman. She is the manic pixie dream girl of Deadpool-inspired comedy, an over-the-top character who hits on half of the people around her and screams at or talks down to the other half.
Harley Quinn is a great comedic character, but the kind of work Black Widow does is not something to laugh at. The Russian spy would view Harley as obnoxious and a liability.
8 Get Along: Catwoman
As a master thief, Catwoman has learned many of the skills that Black Widow also uses in her daily life. Disguise, lockpicking, social engineering, interrogation, and fighting on rooftops are just some of the skill sets they both have mastered.
In fact, the pair have a lot in common, including both being masters of the art of seduction (though Natasha would be less interested in that with Catwoman than vice versa). The two even have similar tastes in black skin-tight catsuits.
7 Hate: Joker
Gotham's Harlequin of Hate is one of the most dangerous people in the DC Universe. He is a sociopathic mastermind whose accomplishments include having bioengineered a deadly gas, his signature Joker Venom, which kills its victims while contorting their faces into rictus grins. To him, the hilarity of a joke is measured in its body count.
Black Widow has dealt with mass killers before. She would deal with Joker by delivering a punchline that would knock him on his kiester...and that would ventilate his skull.
6 Get Along: Lex Luthor
The genius and ego of Lex Luthor make him a dangerous man. He is a man who looks down his nose at gods as though they are beneath him and whose mind has learned to envision all the possibilities among the stars as no one on earth is smart enough to appreciate his genius.
To Black Widow, Lex Luthor is basically just Tony Stark without the mustache. Both are genius billionaires who wear mech suits. Both are also people she can get along with. Whether or not she would share a martini with Lex is uncertain, but the two could definitely work well together.
5 Hate: Doomsday
The spike-fisted musclebound alien Doomsday is among the most lethal and hateful of the villains ever to clash with the Justice League. He taught the world to grieve the death of Superman when he slew the Kryptonian and he has come back from death more than once to finish the job.
Doomsday has the strength of someone like Thanos without any empathy or ideology to temper it. Natasha can handle a lot but she is just not equipped to deal with something that destructive.
4 Get Along: Calculator
While he was once a joke of a character in a ridiculous costume, Calculator has grown over the years. While the superhero community can rely on Oracle for their intelligence, Calculator is an information broker who charges one grand for every question he answers, aiding the word's various villains while getting rich from their crimes.
Good intelligence work is hard to pull off. While Black Widow is more the on-the-ground type of operative, she knows the importance of a digital mole and information broker like Calculator. Such skills are invaluable.
3 Hate: Riddler
Riddler is just as smart as Calculator--and just as ridiculous. In his arrogance, he leaves clues for others to find him and figure out what he is doing. While this may be a compulsion caused by his very real psychological struggles, Riddler's bright costume and penchant for showmanship undermine his credibility.
Natasha has lived her life by working in the shadows and covering her trail. The Riddler is an affront to everything she values. Plus, his riddles are often downright obnoxious.
2 Get Along: Ras Al Ghul
As the immortal leader of the League of Assassins, Ras al Ghul has traveled the world and shaped it his whims. His commitment to saving the planet from humanity has led him to strike from the shadows, sending his assassins to kill for him while also adopting the use of more modern weapons and technology.
A leader of assassins is not that different from a spymaster. Ras' mode of operations are familiar to Black Widow, while his goals are ultimately in the service of a greater good, even if his own legacy and ego are woven into his plans. If Ras managed to keep his dated views on women in check, the two could very well reshape the world together.
1 Hate: Talia Al Ghul
As the favorite daughter of Ras al Ghul, Talia was trained by her father to be an assassin and a leader, but also to bear his heirs with a man he found worthy of her. She has proven herself a competent but cruel leader, even ordering the death of her own son, while never quite living up to what her father would expect of her.
The needless cruelty Talia demonstrates is something that Black Widow would not be impressed by and would see as a mark of failure. Black Widow will almost certainly never have a child, but Talia murdered her own son. This is something that Natasha would see as unconscionable.