Moral Event Horizons in the Digimon franchise.
- Digimon Adventure:
- Vamdemon/Myotismon was the series's first Really Big Bad. If his string of Kick the Dog moments - he tortures and kills his Mooks, he captured Tailmon/Gatomon when she set out looking for her partner on her own and whipped her into a Child Soldier, he has his followers invade the entire city of Tokyo and kidnap its children to weed out the eighth Chosen One, and that's for starters - don't gradually nudge him over the Moral Event Horizon, then Wizardmon's child-scarring death - taking an attack meant to kill Gatomon and Kari, by the way - certainly does. It makes it downright beautiful when the fact that Vamdemon just made it extra personal to Tailmon and, by extension, Hikari triggers Tailmon's evolving into Angewomon and impaling him with an arrow. Even that doesn't stop him, however, and he gets even worse.
- Devimon crossed it when he attempts to flat out murder the smallest, youngest child of the group.
- Etemon (in his Mega form) crosses it when he fires a beam intended for Mimi and winds up killing Leomon instead, starting a franchise tradition. But judging from the gleeful smirk on MetalEtemon's face, he doesn't care!
- While he wasn't as bad as Myotismon or Piedmon, Puppetmon crossed it when he thoughtlessly killed one of his own henchmen who was begging to be taken with him, Machinedramon crossed it when he massacred a whole bunch of Numemon with one blow, and Piedmon crossed it when he led an all-out assault to the Digivice guardians that led to their genocide except for Gennai.
- Secondary villain Datamon crossed the line when he threatened to send the captive Sora falling into the Dark Network pit where her data would be lost for all eternity if Tai didn't give him back the Crest of Love.
- Digimon Adventure tri.: The Mysterious Man crossed it in Part 2 when he murders the Digieggs while disguised as Ken.
- Digimon Frontier: Lucemon crosses it prior to the series by corrupting Cherubimon, driving him to gather all the data in the Digital World so he could absorb it and escape his prison, leading to all the destruction he caused during the series.
- Digimon Data Squad:
- Kurata crosses the line when he specifically made a machine to destroy Digimon permanently and then used it. Upon realizing that he had made it worse, he made it even worse.
- Everyone involved with Kurata's plan, including Hashima, crossed this when they deployed the Gizmon lance. Every last one of them is complicit in the mass murder of an entire city of innocent Digimon.
- Kouki had no qualms about holding a city hostage, not caring about the thousands of lives lost. His comrade Nanami kills Digimon out of a desire to fill a lonely void in her heart, and his other comrade Ivan is doing it to get money for his family. Kouki? Does it For the Evulz.
- MetalPhantomon also crossed it by using the DATS agents' worst fears and memories against them in order to suck out their life energy. Thomas got it particularly bad.
- Digimon Fusion: Despite not doing much, many people were calling for ChuuChuumon's head when he just sat there, bored, watching Damemon slowly die from his wounds. Thus, ChuuChuumon's eventual death was very satisfying.
- Digimon Universe: App Monsters: Leviathan crossed it when it created and placed a child AI to keep watch over a little boy with the sole purpose to gain his trust over years and then break it in order to destroy his morale should ever he become a threat, all because of a familial connection to his creator.
- Digimon Ghost Game tries to show most Digimon as living beings who need to be reasoned with. These few stand out as being utterly incapable of reasoning:
- Sealsdramon already crossed it before his story begins due to the sheer number of his body count, with his episode showing Bokomon to be his 1000th victim.
- Jyureimon crosses it by absorbing humans into his body all for the sake of making himself stronger.
- Arachnemon crosses it by eating the brains of her victims in order to advance her knowledge and evolution.
- Digitamamon crosses it by showing that after a while, he no longer eats humans because he's afraid to be attacked by them, but because he likes the "flavor", going as far as ignoring his own best friend's plea just for the sake of eating another human. Even if said human is his own best friend's partner, and after being told that Digimon can live together with humans.
- The four Chamblemon crossed it when they dragged Ruli, and later Hiro, into their lair and mercilessly brutalize them for food. They could also had been crossed it way before that, especially considering they have a record for keeping women in their lair and pulling mushrooms off them, causing them immense amounts of pain.
- Digimon Survive: The Master might had been murdered a huge amount of children over the centuries to satisfy his desire for revenge, but at least in the Truthful Route our main cast is willing to forgive him over his crimes. These characters in the other hand, committed sins so grievous, that they can never be forgiven by both characters and fans alike:
- If Arukenimon didn't cross it when she led Ryo into letting himself get killed by the Master's Kenzoku, she definitely did when she purposefully destroys Shuuji's already deteriorating sanity, accumulating to him physically beating Lopmon and triggering his dark evolution to Wendigomon, who eats him alive. It doesn't get more cathartic when her boss Piedmon kills her because she was wasting too much time sadistically toying with the children rather than just grabbing them to him directly. She arguably deserved being killed by Piedmon because she wasted too much time sadistically toying with her prey rather than just doling the kids out to him.
- If Piedmon didn't cross it in the Wrathful Route when he repaid Aoi's barely lucid kindness with a brutal beatdown, he definitely did in the Harmonious Route as Boltboutamon where he killed Kaito, Miyuki and the professor in one fell swoop, and threatens to wipe out both worlds as revenge against the Master.
- You know this game is dark when it gives a chance for Takuma, the resident google-headed hero to cross it. If you choose to ditch Agumon and Miyuki to go back home at the branching path of Part 8, you'll get a nasty Downer Ending where all of Takuma's friends and the other world are never heard of again, people in the real world treat him as a pariah over his fight against Piedmon, and the world is just moments away from ending as Takuma relocates from home with his mom. Unlike Shuuji's abuse of Lopmon this is also a conscious choice on Takuma's end instead of him suffering from Sanity Slippage, and he deserves to be spat upon by fans as a Dirty Coward who doomed his world and the other world to certain death in this ending.
