We barely knew Atom (Rhys Ward) and to be honest, his death didn't make this list because we were heartbroken to see him go. Atom's death is devastating because of what it meant for Clarke. When Bellamy, Charlotte and Clarke stumbled upon his body, which had been ravaged by acid fog, Atom begged his friend Bellamy to kill him. However, with Bellamy unable to go through with it, it's Clarke that wound up having to fatally stab Atom in the neck while she did her best to make his death as comfortable as possible, even humming to him as she stuck in the knife.
Ontari (Rhiannon Fish) was never going to be one of our favorite characters, but that doesn't mean we enjoyed watching her die. One of the last Nightbloods in existence, A.L.I.E. made sure Ontari suffered such severe brain damage that she could never take the Flame and become a true commander. After Ontari was rendered unconscious, Clarke underwent a blood transfusion with her, thus allowing Clarke to take the Flame and enter the City of Light. However, in order for this plan to work, Abby had to open Ontari's chest so that Murphy could literally massage the heart of his former lover and keep it beating until Clarke was safe. To say this scene was horrific would be an understatement.
The Season 1 finale was the first time The 100 showed just how ruthless they were willing to get. When the Grounders were preparing to attack the 100's campsite, Clarke and her cohorts used the dropship's rocket fuel to burn the attacking army as they approached, wiping them out instantly without having to lose any men of their own.
A recurring theme of The 100 is whether it's worth it to sacrifice a few for the good of the many, an idea that played out in tragic fashion when Clarke and Lexa learned a missile from Mount Weather was launching at Tondc. In order to maintain Bellamy's cover in Mount Weather, Lexa convinced Clarke to keep the missile a secret, thus condemning over 250 Grounders and Sky People to death. To this day, we still aren't sure whether they made the right choice.
Nyko (Ty Olsson) was a character we really took for granted while he was alive. Ever since he saved Octavia in Season 2, we got used to him always being around to heal and help those in need. That's what made his abrupt death in Season 4 =- when he sacrificed himself to save Luna from a drone =- so hard to swallow: we didn't know how much we loved him until he was already gone.
Oh, Jaha (Isaiah Washington). Although he has the cache of being one of the show's original lead characters, Jaha never really found his place in the series. Unlike Kane, who started off as an antagonist and evolved into a hero, Jaha never really worked his way into our hearts like that. He often helped Clarke, Octavia and Bellamy learn from his mistakes, but Jaha also continued to make them -- huge ones, too. We still haven't quite forgiven him for bringing A.L.I.E. into the series, but that doesn't mean it didn't tug on our heartstrings a little when he died in the bunker not long after Praimfaya.
After Anya (Dichen Lachman) was captured by the Grounders, she went from Clarke's enemy to her unlikely partner. Although the duo betrayed each other multiple times over the course of their uneasy alliance in Season 2, they eventually decide to wipe the slate clean and truly work together to achieve peace. Sadly, that happy moment was soured when a trigger-happy Ark guard shot Anya inthe back as she was walking away from sealing this truce.
We all saw this coming a mile away, but that doesn't mean we weren't a bit heartbroken when, after suffering with depression two seasons, Jasper (Devon Bostick) decided to take his own life. The former source of comedic relief got the idea when Riley accidentally overdosed during a pre-apocalypse party. Shortly afterwards, Jasper died in his best friend Monty's -- but he wasn't the only casualty that day. All the kids who opted out of the bunker fatally overdosed as well, with the exception of Harper, who decided life was worth living.
After Lexa's death, Ontari ensured that she would become the next commander when she slaughtered all the young, innocent Nightbloods in their sleep. To make this whole ordeal that much more gruesome, Ontari then presented the children's' heads in the throne room when she declared her victory.
Most characters in The 100 believe in survival above all else, but not Roan (Zach McGowan). The Ice Nation king lived by a strict code of honor, even if it sometimes put him in danger. During the conclave, Roan refused Echo's illegal help and teamed up with Octavia to stop Luna from winning in order to save humanity. However, just after this new allegiance was formed, Luna drowned Roan in a fountain after they got caught in a downpour of black rain. He deserved better, but if The 100 has taught us anything, you don't always get what you deserve.
Raven had already been through so much on this show, which is why our hearts broke when, after already losing so much, she also lost Sinclair (Alessandro Juliani). Her mentor on the Ark and on the ground, Sinclair lost his life trying to protect Raven from Emerson. Even until his dying breath, all Sinclair could think about was getting Raven to safety, muttering for her to get to the rover until he finally succumbed to his wounds and died.
Wells (Eli Goree) was doomed from the start. He worked hard, always tried to keep the peace and cared so strongly for Clarke, he was willing to get himself arrested and risk death to join her on Earth. But despite any good he did, most of the 100 could not forgive Wells for the one thing he couldn't control: being Jaha's son. That's why Charlotte murdered Wells as vengeance for Jaha executing her parents -- a truly shocking moment that set the stage for much to come.
Maya (Eve Harlow) doesn't get enough credit for being the hero that she was. After the 100 were brought to Mount Weather, Maya quickly proved her bravery when she stepped up and risked her own life countless times to save the lives of the 100. In the end, she had to pay the ultimate price when Bellamy and Clarke decided to irradiate Mount Weather, slaughtering all of the Mountain Men, including poor Maya.
In a scene that gave fans eerie flashbacks to the Culling, Kane and Jaha were forced to gas Skaikru's entire population in order to quell the rebellion and make room for Grounders in the bunker. The leaders then dragged their own unconscious people (including Miller's dad!) outside the bunker where they -- along with the members of the other clans not lucky enough to make the cut -- later perished in praimfaya.
Out of all the massacres The 100 has featured (and boy, have there been a lot), the Culling may have hit us the hardest. In order to give the Ark enough time to repair the life support, 320 residents willingly sacrificed themselves, completely unaware that the Earth was a viable option for survival. One of the first people to volunteer was Tor Lemkin, a devoted father who was willing to sacrifice everything to give his daughter a chance at a real life. Although we barely knew Tor, his noble death was completely heartbreaking and proved how good The 100 could be even at its darkest moments.
After everything Finn (Thomas McDonell) went through, we understand why he went to the dark side and started killing Grounders without a care. That's why we also understand why Clarke had to do what she did. Upon turning himself in to Lexa for punishment, Finn was set to undergo a horribly painful death. In order to spare him the suffering, Clarke secretly stabbed Finn herself, killing the first man she ever truly loved.
If we had to pinpoint the moment we knew The 100 wasn't messing around, it was Charlotte's (Izabela Vidovic) death. After Murphy was nearly hung for Wells' murder, Charlotte wanted to make sure no one else got hurt because of her actions. Faced with the option of turning herself in or watching Murphy kill other camp members (Clarke included), this 12-year-old girl chose a third option: to commit suicide by jumping over a cliff, much to the shock of everyone who witnessed it (us included).
Trying to sum up why Lexa's (Alycia Debnam-Carey) death devastated us is no easy task. Watching Clarke and Lexa fall in love was a bright spot of The 100's second and third season, not only because it brought some much needed hope into the show's dark world, but because how rare it is to see a bisexual love story be handled with such care (that is, when they're portrayed onscreen at all). But right after Lexa and Clarke finally consummated their love, Lexa was killed in a tragic accident that left the entire 100 fandom reeling. The repercussions of Lexa's death were so monumental, they went far beyond just the CW show. Lexa's unfortunate death helped bring national attention to the "Bury Your Gays" trope plaguing Hollywood. It inspired creator Jason Rothenberg to pen an emotional letter of apology to the fans in which he promised to do better, and it even resulted in a LGBTQ entertainment convention, ClexaCon, being named in the former couple's honor.
We had barely begun to recover from Lexa's death when The 100 dealt us the most painful blow yet. After speaking out against the horrific treatment the sick Grounders were receiving from Skaikru, Lincoln (Ricky Whittle) was locked up and eventually sentenced to death. Octavia attempted to rescue Lincoln, but he refused to allow his fellow Grounders to die just to save himself. Because of that, Lincoln was marched outside and forced to kneel in the mud as Pike shot him in the head, but not until after he sent Octavia one final message: "May we meet again."