Underground Emperor Zeba. Tube's dictator who has absolutely no compunction about killing or punishing his subordinates. His monstrosity is finally revealed in the final episodes where it turns out that he is actually the spawn of Rizal Doggler, a malignant creature who tried to usurped the throne and was defeated by the original Tube royal family. After which he ate his dying father in order to become stronger. Driven by a seething hatred against humans from both sides of the crust, it proceeds to destroy the rest of the original family save Ial and Igam, taking over as emperor and corrupting the peaceful Tube into becoming a militaristic Crapsack World using enslaved underground humans in an attempt to reach the surface world and extend its malicious grip.
Surprisingly, Ragorn looks less of a Complete Monster in comparison to Bouma Princess Jarmin. While she is nonetheless loyal to Ragorn, she has a really nasty thing in manipulating her allies' emotions. For instance, during an episode featuring an Ice-Fire Bouma siblings, the Ice Bouma reconsidered in not fighting the Turborangers out of concern for his brother. Jarmin's solution? Incite the Fire Bouma to try and kill off his brother. And once that's done, she combines them into one monster. Her biggest Moral Event Horizon, however, was against the Bell Chime Bouma, a female monster whose tribe was locked away by Jarmin herself inside a bell chime and threatened her into fighting the Turborangers; in this case, get Youhei/Blue Turbo mesmerized and alienated from the team or else the whole tribe is destroyed. Oh, and she still WHIPS her when she's not seriously fighting. And when the Turborangers break the spell? There comes Jarmin, destroying the bell chime containing the whole tribe, in front of the Bouma herself, and KILLS her right after, THEN turn her into a giant monster for the Turborangers to fight. Yowch, nasty bitch.
In particular, Jarmin herself being a Complete Monster is an accomplishment amongst female Sentai villains. Usually, in other Sentai series, villainesses are treated with sympathy or don't surpass the boys in terms of depravity (Shibolena, Venus, etc. come to mind). If they do, like Grandienne below, it's because of her position as the Big Bad. Jarmin was merely the Dark Chick, an underling, and yet she surpasses Ragorn in depravity.
Radiguet is often considered the worst of the lot. He proclaims himself God of any dimensions he's invading and then happily commits genocide on the dimension. His main justification is that 'Anyone else not a member of Vyram are like bugs that deserve to be squashed,' and even amongst Vyram members, he's still plotting to rule them all. When the former Vyram Empress Juza arrives, Radiguet quickly becomes The Starscream, though that backfired for awhile, which turned him into an amnesiac human, gaining a Morality Pet; but when he remembers his past, he returned to his usual self; and when his Morality Pet calls him out that he could still be human and able to love...he turns her offer down by killing her, saying that there is no way in hell he could love, which he considers 'a disgusting human activity.' Oh, and he's also the one who brainwashed Ryuu's lover Rie into becoming one of the Vyram elites, Maria, for no reason than probably For the Evulz. And when she regained her senses and backstabbed Radiguet, he retaliated by killing her, but not just because he wants to punish traitors, but majorly because he just wants to give the middle finger to Ryuu/Red Hawk by robbing him of the joy of his long-awaited reunion with Rie. Radiguet may lack the Nightmare Fuel-tastic qualities from the future Sentai villains, but if there's one thing he had over them, it would be his high level of dastardliness and despicability.
As Jetman is considered a Darker and Edgier sentai, a human Complete Monster can be found in the form of Commander Ichijou. As a military general, he was driven by Envy of Commander Aya and founded the Neo Jetman team and had them replace the actual Jetman. Then he proceeds to treat his Neo Jetman team as expendables, sending them on dangerous missions and not letting them retreat until they finish the mission, practically sending them to die while he rests easy in his office. When the Neo Jetman found out that the original Jetman can recover, he purposely lied that recovery is impossible so the Jetman can be officially expelled and he can make Aya suffer his 'humiliation' of not being selected for being a commander in the past. In other words, as long as his superiority is assured, he doesn't care what needs to be sacrificed, including other humans. Radiguet did once say Humans Are Bastards...he may be partially right if Ichijou existed.
Colonel Shadam is a pretty nasty version. Responsible for many bad things in the series on top of the fact that he cares nothing for his two sons and wife, his amazingly abusive treatment to Akomaru is the ultimate proof of this. He shows zero honor at that: when Doushi Kaku showed mercy for him and the tables were turned for his side, Shadam instead uses the chance to mercilessly and brutally murder Kaku through utter Curb-Stomp Battle. He also doesn't give one freaking shit about any of his subordinate, and the fact that they are clay dolls created by him and he plans to discard them once they are useless for him make this even worse. Even worse, that includes his apparent master. Yes. Basically, this guy gives no shit about his friends, his child, his master, or HIS WHOLE FRIKKIN' RACE. It's all about him in his head. It's particularly cathartic when he met his demise...and gets revealed that he toois a clay doll created by the original Shadam thousands of years ago and crumbles while begging Ryou for help...
Commander Guirail. Unlike Noble Demon Yugande, who is honorable and dislikes underhanded tactics, Guirail has absolutely no qualms about doing whatever he feels is necessary to win. His first appearance even has him using CHILDREN as human shields. He also has no loyalty to anyone and is willing to hurt or possibly kill his comrades. Ultimately, when Guirail severely injures Yugande by using him as a Human Shield against the Megarangers, Hinelar decides to end it by offering Guirail a Psycho Serum in the guise of a power-up to turn Guirail into a mindless One-Winged Angel. Guirail is soon the first to be killed by the Megarangers' Mid Season Upgrade mecha. Seeing him writhing in agony due to the serum before getting killed by the Megarangers is quite satisfying.
Grand Witch Grandienne, who deliberately sent her children out to die, brainwashed one to kill another on several occasions, banished one to Hell, and resurrected two of them as brainwashed zombies. As fitting of the family theme in GoGoFive, Grandienne stands for everything the Tatsumi family bond isn't. She has to be killed multiple times; apparently, just one Karmic Death was too kind for this monster.
The Hell's Gate prisoners in Mirai Sentai Timeranger were regarded as the most vile and dangerous criminals of the 30th century. One whose atrocities stand out even among his peers was Emboss, a victim of a man-made contagion who refused a cure because he relished the opportunity to spread the virus to others.
Captain Ryuya, Tatsuya Asami's Identical Grandson (give or take a few dozen 'greats'), was the ultimate mastermind behind everything that occurred in the series — from the initial escape of Don Dolneiro to Gien's insanity. In other words, he was responsible for the crisis that took place in the finale (he had seen two futures — one in which 1/3 of the 21st century is destroyed and one in which the 31st century ceases to exist). The worst part is why he manipulated everything that happened — because he saw that both futures would result in his demise.
Most of the Alienizers in Tokusou Sentai Dekaranger, particularly Agent Abrellar, who'd sell lots of weapons supporting galaxy-destroying wars for profit and fun to most of the Alienizers, regardless of how many lives were taken. One galaxy destroyed, he moves to another galaxy to generate profit and destruction.
Oh, it's even worse for Abrella: most of the Alienizers have some sort of twisted logic to justify their actions and are shown to have some modicum of standards to their deeds. Aburella, however, treats any and all crime as a business opportunity, and it doesn't matter if you're destroying entire cities, selling slaves, pawning stolen merchandise, or filming child pornography, as long as the price is right, he'll be more than happy to sell you the tools you need to further your enterprise. And his Villainous Breakdown near the end of the series? All caused merely because the Dekarangers were ruining his transactions. Yes, Aburella himself caused a citywide destruction spree and nearly destroyed the whole of the Space Police simply so he could keep his job. He and Pigma would get along just fine...
And then there's his minion, the Hades GodCyclops. After a brief skirmish with the Magirangers, he vanishes and begins firing upon them from multiple directions at once, deliberately stringing them along into thinking they've figured out how to escape his bullets, only to take one of them down. When he takes down Urara, Tsubasa experiences a total nervous breakdown, and Cyclops simply exclaims that there's no greater pleasure than watching someone's mind break. Seeing Tsubasa beat him at his own game is one of the most cathartic moments in all of sentai.
Long the Immortal Dragon. His motives boiled down to "I'm Immortal. Bored. Now, let's destroy the world for fun!". Just about every bad thing that happened in the Gekiranger world (the formation of Kenma, as well as the death of Rio's family and setting him up to fall to the dark side) can be traced back to Long's action to relieve his boredom, which includes the death and suffering of humanity, but Long gives no damn at all, for he thinks that he's an ancient being that has 'guided' humanity, and thus has the right to screw them over in any way he wants.
Sujigarano Akumaro was sinister, even for the Gedoushu. His ultimate plan was to cause sufficient suffering to drive wedges of said suffering into six precise locations, as part of a ritual to open the way to Hell so that he could taste absolute human suffering — even though this ritual would destroy both the human world and the Sanzu River. Also, he made Fuwa Juzo's sword from Juzo's dead parents, whom he murdered himself. His monstrosity extends to even his Ayakashi, who seem specifically made to cause as much suffering as possible to further his goal.
Fuwa Juzo was a remorseless Blood Knight to the point that even his fellow Gedoushu didn't trust him; he even only became a Gedoushu in the first place so that he could keep killing in spite of his sickness. Akumaro saw potential in him for his ability to walk the line between humanity and the Gedoushu and sought to use him to open the gates of Hell. However, he throws a sharp wrench into the plan, declaring that he already knew that his sword made by Akumaro was made of his parents, and, moreover, he didn't care.
Bruajira of The Messiah, a Manipulative Bastard of the highest order, for starters he was a Gosei Angel until he decided that power was the only thing to live for, he killed and cannibalized his FRIENDS! just for that and then went back in time in order to take over earth, he was also a double crossing SOB who betrayed 4 seperate evil factions (Gedoshou from Goseiger vs. Shinkenger included), However YMMV, since he does have traits of a Magnificent Bastard
