The Arrowverse, named after the show that launched a thousand spin offs, is probably the most popular and heroic extended TV universe to this day. With "Crisis On Infinite Earths" looming just around the corner, the Arrowverse is set to also include the likes of Black Lightning and Smallville in its rostra.
Despite the many, many superheroes that have graced our small screens however, these heroes sure do make a lot of mistakes. Whether they're just trying to do what they think is best, or if they've been taken over by external forces, the main characters of the Arrowverse have committed some truly awful acts.
10 Barry Allen/The Flash - Killing Cisco's Brother
Season 2 of The Flash was quite dark in some aspects. There was a new villain in the form of Zoom, who was not quite as chilling as the Reverse Flash but still creepy regardless, and there were also some shocking moments, none quite as devastating for the titular hero as the death of Barry's father.
This event leads Barry to go back in time and save his mother, thus changing his entire future. However, when Barry eventually put time back on track there were some absolutely tragic consequences; Cisco's brother Dante, who the gang had helped in the past, was dead and Barry was partly to blame.
9 Sara Lance/White Canary - Joining The League Of Assassins
Anything which involves the word 'assassins' cannot be good so it is quite surprising that the White Canary's journey to heroism began in the actual League of Assassins. In fairness to Sara Lance, her situation was pretty dire and it was either that or succumb to a watery grave.
However, it was a brutal and bloody start to her journey and for a long while, killing was all she knew. What made this even worse though is that when she finally returned to Starling City, she refused to let any of her friends or family know that she was in fact alive. For a superhero, this was a pretty lame move.
8 Kara Danvers/Supergirl - Lying To Lena Luthor
This was a difficult one because like her cousin, Supergirl is an extremely honorable character and is probably the most worthy hero in the entire Arrowverse. Therefore, she doesn't often make any severe mistakes. That said, her treatment of her best friend, Lena, leaves a lot to be desired.
Lena Luthor began as a recurring character in Season 2 of Supergirl but went on to become one of the most complex and unique characters in the Arrowverse due to her disdain for her family's legacy. She proved multiple times that she was a good person and so Kara should have entrusted her with her secret, especially since literally everyone else knew at that point apart from Lena.
7 Laurel Lance/Black Siren - Killing Black Canary's Lover
Who said every main character in the Arrowverse had to be a superhero? One of the franchise's biggest successes is its first-rate bad guys and the Laurel from Earth 2 was a surprisingly effective supervillain.
Black Siren's most shocking (and horrifying) moment occurred halfway through Season 6 of Arrow. She had managed to capture Black Canary's boyfriend, Vincent Sobel aka Vigilante, and had tortured him until he was nearly dead. Just as Black Canary arrived on the scene Laurel killed him, and Oliver and Quentin Lance's hopes that she could be redeemed seemed to die right alongside.
6 Oliver Queen/Green Arrow - His Status As A Murderer
One of the overarching themes of Arrow throughout its eight seasons is Oliver's struggle as to whether he is a hero or a villain. Granted, if Oliver hadn't become the Green Arrow then a lot of people would be dead and Star City would have become a literal hell on earth.
Contrastingly, the series's main protagonist has an unnervingly high body count to his name, a lot higher than even some villains. Most of Oliver's targets arguably deserved some sort of punishment but to act as judge, jury and executioner requires a massive God complex, which is the antithesis of what heroes should be.
5 Alex Danvers - Killing Kara's Aunt
The Danvers sisters are the closest of all siblings in the Arrowverse. However, like all siblings, they do squabble and make mistakes. In Alex's case though, it was less of a mistake and more of an intentional stab in the back (with a kryptonite blade).
Astra, Kara's slightly evil aunt, was the main antagonist for the first half of Season 1 of Supergirl. However, she clearly showed affection for her niece which was her one redeeming quality. Kara was close to getting through to her but after Astra's attack on J'onn J'onzz, Alex was forced to kill her to save her friend.
4 Harrison Wells/Reverse Flash - Harrison Wells Is Eobard Thawne
This plot twist could be seen from a mile away but it's thanks to Tom Cavanagh's performance and some top notch writing that Reverse Flash remains Barry Allen's greatest foe to this day. Apart from the audience, everyone at Star Labs saw Wells as a father figure and trusted him with their lives.
When they eventually found out Wells's true identity they were both hurt and appalled. Reverse Flash had done some horrible things even before The Flash had begun and viewers were forced to watch him kill fan-favorite characters like Cisco and even Barry and Iris's daughter Nora.
3 Malcolm Merlyn/the Dark Archer - Killing His Own Son
Malcom Merlyn was an extremely complex and entertaining villain who lasted for a respectable five seasons before sacrificing himself to save his daughter. Unfortunately, this in no way makes up for the fact that four years earlier, he inadvertently killed his own son and Oliver's best friend, Tommy Merlyn.
Malcolm was Arrow's first main antagonist whose evil plan was to level the Glades using an earthquake machine in order to rebuild a 'better' city. This resulted in thousands of deaths, including Tommy who went to the Glades to save Laurel who was trapped in a burning building. Although Malcolm never meant for his son to get harmed, he was still directly responsible.
2 Thea Queen/Speedy - Killing Sara Lance
The mystery of who killed Sara Lance played a big part in the first half of Arrow's third season. It was an act that no one saw coming and certainly set up the season in preparation for even bigger events. However, the reveal that it was Oliver's own sister that killed Sara was met with even more disbelief than the murder itself.
Of course, it later transpired that Thea was being controlled by none other than her biological father Malcolm Merlyn and so she couldn't be held responsible for her actions. However, Thea had chosen to go with Malcolm at the end of Season 2. If she had just decided to remain in Starling City, then Sara would never have died.
1 Caitlin Snow/Killer Frost - Joining Forces With Savitar
In recent seasons of The Flash, Killer Frost has become more of an ally to Team Flash, helping out with several cases and providing some cute, if not weird, conversations with her warmer alter ego. However, when she first appeared, Killer Frost was really, well, frosty.
In Season 3, Caitlin started to exhibit peculiar signs, which the gang managed to miraculously ignore until it was too late. Killer Frost arrived in a big way and proceeded to wreak havoc, teaming up with the main villain Savitar. Given that Savitar actually killed the love of Barry's life, there should have been a part of Caitlin that knew better.