History MoralEventHorizon / KamenRider

** Doctor Prospect from the V-Cinema prequel detailing the origins of Kamen Rider Eternal. What makes him a devil in human form is best summed up in two words: "Heaven's Fall".

** Two words: "Heaven's Fall".

** [[spoiler:Parado]] crosses this when [[spoiler: he kills Kuroto by infecting him with a lethal dosage of the Bugster Virus. Any other situation, this would qualify as both a case of BadGuysDoTheDirtyWork and KickTheSonOfABitch but the problem is that Kuroto was already rendered a non-threat by the time Parado got to him.]] Though if you think that's not ''that'' bad, he gleefully skips across the horizon by [[spoiler:completing Kamen Rider Chronicle and announcing its true intent: human extinction, apparently to show them what it means to be beaten like him]].

* '' Series/KamenRiderOutsiders'': [[spoiler:Zein crossed it in episode 4 along with the reveal of its master plan with [[DeadlyGame Kamen Rider Chronicle]]-- by creating a cannon fodder of Ride Players to be used as {{Sacrificial Lamb}}s against the Outsiders, essentially tricking mankind into [[InYourNatureToDestroyYourselves slaughtering one another]]. Zein possesses its host, the alternate Yuto Sakurai, who viewed his hesitation after listening to Brain's pleas as insubordination, against his will and proceeded to impersonate Nico Saiba to manipulate Genm Corp into relaunching Rider Chronicle.]]

* '' Series/KamenRiderOutsiders'': [[spoiler:Zein crossed it in episode 4 along with the reveal of its master plan with [[DeadlyGame Kamen Rider Chronicle]]-- by creating a cannon fodder of Ride Players to be used as {{Sacrificial Lamb}}s against the Outsiders, essentially tricking mankind into [[InYourNatureToDestroyYourselves slaughtering one another]]. Zein possesses its host, the alternate Yuto Sakurai, who viewed his hesitation after the listening to Brain's pleas as insubordination, against his will and proceeded to impersonate Nico Saiba to manipulate Genm Corp into relaunching Rider Chronicle.]]

** Beroba, almost ''every damn time''. One specific example is [[spoiler:when, after seeing that Ace has shown up in Neon's stead to fight the Jyamato and blown her plans out of the water, she crosses it by revealing the dark truth about Neon, who is actually a replacement for Kousei's dead daughter that was created by the Goddess of Creation to the audience which causes Neon's "fans" to raze her all while sadistically laughing after she tells it in #29. It's telling when, for the first time, Ace becomes not only ''[[TranquilFury pissed]]'', but outright declare that ThisIsUnforgivable and vows to take Beroba down.]]

** Beroba, almost ''every damn time''. One specific examples is [[spoiler:when, after seeing that Ace has shown up in Neon's stead to fight the Jyamato and blown her plans out of the water, she crosses it by revealing the dark truth about Neon, who is actually a replacement for Kousei's dead daughter that was created by the Goddess of Creation to the audience which causes Neon's "fans" to raze her all while sadistically laughing after she tells it in #29. It's telling when, for the first time, Ace becomes not only ''[[TranquilFury pissed]]'', but outright declare that ThisIsUnforgivable and vows to take Beroba down.]]

** Beroba, almost ''every damn time''.

* ''Series/KamenRiderGeats'': [[spoiler:Girori crosses it when he not only uses the Vision Driver's powers to brainwash the other riders, but also turning Win Hareruya into a suicide bomber with it to eliminate Ace Ukiyo.]]

** Blood Stalk/[[spoiler:Evolto]] crosses it when its revealed that he orchestrated the death of [[spoiler:Ryuga's girlfriend]] specifically to hurt him and is planning to end all life on the planet. [[spoiler: And then there's the fact that he's already done it ''countless'' times before all for the sake of power. He only stopped at Mars because he was too damaged by Vernage to continue.]]

** Utsumi crosses it when he [[spoiler: goes insane and pledges his loyalty to Evolto, knowing full well that he plans to destroy the world.]] [[spoiler: Even when it is revealed that it was just an act so that Utsumi could get a hold of an Evol Driver so that he could personally avenge Namba.]]

* ''Series/KamenRiderBlackSun'': Wataru Igaki crosses this when he orders his anti-Kaijin group to [[spoiler:beat Shunsuke to death and then lynch him as a warning to other Kaijins]].

* ''Series/KamenRiderRevice'': Olteca crossed it in #18 when he sacrificed Julio's friend Yosuke to a Gifftarian to as an act of spite and with a [[SlasherSmile smile]] on his face. If that wasn't enough, then attempting to off Julio while he was still upset would.

** [[spoiler: Tachibana]] and 4C by proxy in ''The Last Judgement,'' all too willing to [[spoiler: [[HarmfulToMinors create and groom artificial Amazon children to be cultivated and sold to the rich]]]] out of [[ShootTheShaggyDog petty rage toward the practically-extinct Amazons]] under the justification of a "meat shortage."

** [[spoiler:Taiga]] of all people crosses this [[spoiler:in Episode 8 when he kidnaps the Bugster, forcing Emu and Hiiro to fight him in order to save a completely innocent person's life]], followed immediately by [[spoiler:him going Level 3 to bring death from above to the two, and finally baiting Ex-Aid, who is completely focused on saving the patient's life, with the Bugster so that he can MoreDakka him to oblivion.]]

** In episode 41, [[spoiler: Hiryu, instead of learning to forgive Sougo, chooses to become Another Zi-O once more, subjects the world under a tyrannical rule and harms millions of people just to spite Sougo.]] In Final Stage, [[spoiler: he still goes for one last attempt by taking over Quartzer as the new Barlckxs to collect the Showa Ridewatches, ultimately becoming Another Oma Zi-O. Now planning to wipe out the Heisei era altogether [[BornInTheWrongCentury because he feels he shouldn't have been born in it.]]]]

** Horobi has one in Episode 6 when ''[[PsychopathicManchild Jin]]'' [[EvenEvilHasStandards can't actually bring himself to turn a certain [=HumaGear=] into the]] MonsterOfTheWeek, so he responds by [[spoiler:forcefully reprogramming Jin, revealed to be [=HumaGear=] himself, into doing it anyway.]]
** Gai Amatsu crossed it before any of them considering [[spoiler:he's responsible for giving the Ark its mentality which gave rise to [=MetsubouJinrai=].NET and them in the first place]]. If that wasn't enough to prove he jumped into the horizon, then ep.29 showed he ''cannonballed into multiple moral event horizons'' by [[spoiler: mentally torturing Fuwa with the AI chip in his head and not batting a single eye doing so while the latter is screaming in pain. And he doesn't even let up after he throws the Rampage Gatling Key at him. The episode also shows how he doesn't even care about the well-being of other people, seeing them as merely tools that must follow his directives all to further his agenda in controlling Hiden Intelligence.]]

** [[spoiler:The current Master Logos crosses this when he goads the nations of the world into warring with each other, and starts destroying entire cities when violence doesn't break out.]]