When in a position of leadership or power, different individuals tend to act in different ways, defining the general nature of their rule. In anime, the ruthless side of this role is often reprised, as characters are usually there to serve an important antagonistic purpose. They strike as much fear into their opponents as they do their subjects, treating both sides with the same amount of contempt.
These characters may take the form of regular humans or even supernatural beings whose status is reinforced by their absurd strength. They are also cruel, merciless dictators who will not hesitate to cause harm even if it results in the suffering of their own people.
10 Kagemitsu Daigo – Dororo
Kagemitsu was a power-hungry man who served as the Lord of Ishikawa in mid-Muromachi Japan. To expand his influence and hopefully rule over the entire country one day, Kagemistu made a pact with 12 demons in exchange for the body parts of his newborn son, Hyakkimaru. They were then set loose across the land, causing havoc wherever they went.
Though you could argue that he had the best interests of his region in mind, his methods were less than ideal. Kagemitsu was not above sending soldiers to kill innocent villagers regardless of age, gender, or status. He was also comfortable with letting the demons roam freely as long as his ambition could be realized, going as far as to pursue Hyakkimaru when he learned of the young man's quest to destroy the evil spirits.
9 Charles Zi Britannia – Code Geass
Charles was the 98th emperor of the Britannian empire and the leader of the most powerful military force in the world. He saw humanity as a doomed race, bound to be engaged in conflict for all eternity, and as a result, sought to destroy the current state of the world.
By eliminating free will and merging the consciousnesses of the living and the dead, Charles thought this was the only way to ensure everlasting peace. However, the irony of his methods was glaringly apparent. For one who claimed to be pursuing world peace, he caused great suffering and destruction to the territories he took over. He also exiled Lelouch and the blind Nunally, his own children, after an attack on the Imperial Palace killed their mother.
8 Baraggan Louisenbairn – Bleach
The former God-king of Hueco Mundo and ruler of Las Noches, Baraggan was a powerful being who was largely unmatched in the realm of the hollows. Aizen, an outsider, later defeated him, and even then, he barely showed any care for his fellow Espada. He represents the aspect of death and, as a result, constantly belittles his opponents due to the finite nature of their existence.
While he was still the King of Hueco Mundo, not much was seen of Baraggan’s actual leadership qualities. However, it was apparent he didn’t appreciate his role or value those under him. He was extremely bored and claimed that he would have split his army into two different factions and driven them to kill each other.
7 Lordgenome – Gurren Lagann
Lordgenome was initially very similar to the heroes of the Gurren Lagann story. In his earlier years, he waged war against the anti-spirals and sought to destroy them for the sake of humanity. However, after he was informed of the spiral nemesis, he lost all hope of victory and chose to drive humanity underground to cull the use of spiral power.
Despite being a human himself, he entered into an agreement with the anti-spirals and created beastmen to eliminate any humans they found traversing the surface of the earth. He also often abducted girls from a specific village to bear his offspring and, in most cases, ended up killing them before they properly matured. He may have previously held noble intentions, but his personality eventually devolved into one of a ruthless tyrant.
6 Meruem – Hunter x Hunter
Meruem is a complex character with multiple interesting aspects to his personality, most of which developed after his interactions with Komugi and his battle with Netero. Before those events, however, he was a crude being who valued himself far above anyone else.
As soon as he emerged from his mother's womb, his priorities were clear as he completely ignored the unbearable pain he had caused her. The prematurely born Chimera Ant King then proceeded to kill two others of his kind for acts one could hardly consider infractions. Though he understandably saw and treated humans as livestock, for most of his early life, he didn't treat his fellow Chimera Ants much better.
5 Muzan Kibutsuji – Demon Slayer
Muzan is the progenitor of all demons and is known as the Demon King in the world of Demon Slayer. He is the most powerful of his kind and has been around for roughly a thousand years. He creates demons by infusing humans with certain amounts of his blood. From then on, they either swear undying fealty to him or live in great fear of him for the rest of their lives.
He is an extremely prideful being who will not hesitate to kill the demons he creates if they don’t measure up to his expectations. On one occasion, he mercilessly killed multiple members of the Lower Ranks simply because he was dissatisfied with their performances and no longer saw any use for them. He is also quite strict with the Upper Ranks, as even though Akaza killed a hashira, he was still berated for not doing more.
4 Donquixote – One Piece
Doflamingo, the ostentatiously dressed captain of the Doflamingo Pirates, is a manipulative, cunning, and powerful character. Prior to his imprisonment, he acted as the king of Dressrosa and was actually liked by many of his people. However, this was due to the fact that they were unaware of the true state of their country.
Doflamingo had, in truth, forcefully taken over Dressrosa, using underhanded tactics to paint the former king as a villain. He then proceeded to turn a large number of people in the country into toys, erasing their memories and robbing them of their free will. As his reign was coming to an end, he also attempted to eradicate all life on the island and made its citizens fight each other to the death.
3 Frieza – Dragon Ball
Frieza is a cruel and sadistic being with an ego large enough to match his incredible strength. He is one of Goku's most iconic opponents and has an unquenchable thirst for power, destruction, and glory. He is also referred to as the emperor of Universe 7, inheriting the title from his father.
He commands a large fleet of soldiers and finds them expendable at best. He delivers extreme punishment to his troops if they display a huge lack of incompetence and will eradicate them if his displeasure is great enough. Even when faultless, he doesn't mind killing hundreds of soldiers and treating them like collateral damage, as shown when he destroyed Planet Vegeta and powered up to fight Goku in Dragon Ball Super.
2 Fritz The First – Attack On Titan
Around two thousand years prior to the events of Attack On Titan, Fritz ruled as the King of Eldia. He was a cruel man who ordered raids on villages and mutilated slaves for minor offenses. He also had a massive thirst for power and could still envision ruling the world after his death through his people.
He was the first king to be exposed to the power of the titans, and he wasted no time weaponizing that power. Desperate to pass it on after the death of the first holder Ymir, he even drove his own children to cannibalism and made them eat their mother.
1 Kaido – One Piece
Kaido is the leader of the Beast Pirates as well as the man who conquered the land of Wano. He made the country a living hell for most of its residents, forcing many into hard labor and leaving a large population in poverty. The only region in the country that seemed prosperous was the Flower Capital, but even then, individuals residing within it were required to have money or face exile.
The powerful pirate also set up factories all around the country for the production of artificial devil fruits. This action ended up polluting most of the country's rivers and making its lands barren, further inconveniencing the distressed citizens.