Natasha Romanova, better known as Black Widow, a prominent member of the Avengers and a S.H.I.E.L.D. agent, is an expert spy and a skilled assassin. Because of this, plenty of Marvel characters failed to survive an encounter with her.
While her capability to kill is even alluded to in her alias, she's an assassin, meaning she's better at handling targets than taking down people on a larger scale. Being a comic book character also complicates things, since characters rarely stay dead. Black Widow could shoot Jean Grey and Beast dead, only for them to turn out to be aliens just posing as the characters, meaning there is no blood on her hands. Being able to appear in multiple parallel universes, where characters can be simultaneously alive and dead, can also help in this regard.
10 Richard Frampton Had His Missile Redirected At Him
Richard Frampton was an Australian CEO of Sojourn Enterprises, as well as a member of the Ten Rings. He hired an assassin named Sofia to collect software for him, which would bring her into contact with Black Widow herself.
Upon learning the true nature of the software — a missile launch — Black Widow redirected the coordinates to attack Frampton himself, ultimately killing him.
9 Family Ties Did Not Save Vindiktor
In comics, superheroes and siblings don't always mix, with one often being the good one and the other being the bad one. Or at least with one less morally ambiguous than the other. Black Widow was separated from her brother, Vindiktor, when they were children due in part to a house fire, and their reunion would not be a happy one.
He attacked her, attempting to kill her, but he underestimated how skilled his sister had become in the years since they had last met, with her killing him instead.
8 Taking Down Galactus Involved Team Work & Werewolves
There have been various counterparts to Black Widow over the years in the different universes of the Marvel comics. Marvel Zombies, for example, even showed a Black Widow as a werewolf.
Even in this form, she appeared quite dangerous, once joining with other werewolves to take down and eventually eat Galactus. To be fair, she was one of a few werewolves during the attack, but a team effort is just sometimes more effective than a one-on-one fight.
7 Black Widow Had To Be Careful Taking Down The Prophet
The Prophet was the head of the Chaos organization, who managed to manipulate events having some foresight as to what would happen in the future.
Black Widow was able to subdue him, but it was no easy task. She ended up stabbing him in the throat and dumping his body in ice water, having just crawled out of the freezing water herself.
6 Sofia Was Tricked Into Talking Herself To Death
Black Widow encountered Sofia while she was collecting dangerous software for Richard Frampton. However, their history goes a little deeper than that, as she was once a Bulgarian orphan Black Widow rescued from a prostitution ring. Unfortunately, her admiration for the heroine grew to an obsession with Sofia wanting to take Black Widow's mantle for herself.
Sofia, however, would meet her end during the Frampton case. In order to foil their plan, Black Widow tricked Sofia into talking long enough to be too distracted to notice the Jericho launch from the compound, effectively killing her.
5 Jasper Sitwell At Least Came Back As A Zombie
Jasper Sitwell had a prestigious resume; he went from being a top S.H.I.E.L.D. agent to even working for Stark Industries. Unfortunately, he was in the wrong place at the wrong time, once encountering a brainwashed Black Widow and dying at her hands, effectively taking a fatal blow meant for Nick Fury.
Being a comic book character, death wasn't necessarily the initial end for him; he later returned as a zombie. In his newly undead state, he would later be seen working for the Howling Commandos.
4 Edwin Jarvis Was Right To Be Suspicious
The benefit of being a comic book character is that, with all those universes a character can exist in, they can do whatever the writer imagines without the "real" version of said character enduring any consequences.
In the Ultimate universe, Black Widow managed to kill Tony Stark's butler, Edwin Jarvis, who had been suspicious of her after she was starting a relationship with Stark. This version of events appeared to have a lasting impact on both Stark and Black Widow, who used the slaying to unmask her true colors.
3 Hawkeye's Family Couldn't Escape Ultimate Black Widow
The Ultimate universe arguably has Black Widow at what fans consider to be her worst; she still poses as a hero but is in reality a crazed terrorist. Although she's portrayed as a close friend to Clint Barton, better known as Hawkeye, she didn't show him mercy at the end, going so far as to send a black ops team to his own home.
While Hawkeye himself wasn't there, his wife and children were and they soon met a cruel end at the hands of Black Widow and her team.
2 Spider-Man Couldn't Survive A One-Panel Gag
This one technically comes from a "What If...?" story, meaning the character is okay in most other continuities, but not so much in this story. Essentially, Black Widow and Spider-Man have become husband and wife, an obvious nod to their arachnid-themed names, and possibly a joke on Spider-Man's feelings for redheads.
Unfortunately, the names are taken a little too literally, with Black Widow not only killing but going so far as to actually eat her doomed husband, leaving nothing but a skinsuit and bones.
1 Black Widow Chose The Earth Over Ivan Petrovich
Ivan Petrovich was a man who served as Black Widow's guardian in her past who disappeared from her life, in part due to unreturned feelings from his charge.
When they reunited years later, Ivan had become a disturbed cyborg with dwindling sanity. When he sought nuclear attacks against the Earth, Black Widow felt compelled to kill him for the greater good, effectively tearing a hole through him.