Most anime villains may be diabolical, heartless monsters, but they're often not beyond reason. Typically, they'll be willing to compromise with the hero, reconsider their position, or follow some sort of plan that puts them in a better position later on.
However, there are a handful of antagonists so blatantly unreasonable that they cannot be bargained with, pleaded to, or otherwise dissuaded. They are so singularly determined to accomplish their respective goals or to commit atrocities that not even the world's most persuasive speaker would be able to convince them otherwise.
10 The Supreme Deity Saw Herself As Beyond Criticism
Seven Deadly Sins
As the leader of the angels in Seven Deadly Sins, the Supreme Deity felt as if the rules that applied to others did not apply to her. She was so single-mindedly convinced that the Demon Clan must be destroyed that she put a curse on her own daughter for defying her.
Additionally, the Supreme Deity sent her four archangels to win Britannia on her behalf. Although they were comfortable fighting alongside humanity, they did not have its best interest in mind.
9 Mad Pierrot Was Too Broken To Change
Cowboy Bebop
Mad Pierrot was easily the strongest villain in Cowboy Bebop. However, he likely wouldn't have wished to be this way. After all, his power came from a series of cruel experiments that traumatized him to the point of no return.
Although Pierrot had revenge against the people who wronged him, it was too late for him to go back to the person he once was. Instead, he wanders the lonely nights in search of victims to kill, and he's taken precautions to ensure no one who sees him survives.
8 Spec Had No Humanity To Be Reasoned With
Baki
Out of all escaped convicts in Baki, Spec was by far the least reasonable. Unlike Dorian, he did not get caught up in the paradox of never being defeated and was so unstable that he shot himself through the cheek to prove a point.
Spec was so driven by a destructive purpose that it literally kept his body together despite being in his senior years. After getting defeated by Hanayama, he shriveled up into a desiccated husk of a man. In the end, Spec's bloodlust and purpose proved a greater strength than any underhanded technique he used.
7 Shigaraki Was Indoctrinated By All For One
My Hero Academia
Having accidentally killed his family at a young age, My Hero Academia's Tomura Shigaraki got adopted by All For One. Throughout his childhood, he was indoctrinated by the villain, who blamed his poor childhood directly on the heroes of Japan.
As an adult, Shigaraki has deliberately made it virtually impossible to reason with him. He refuses to compromise with any of the heroes and only played along with Re-Destro momentarily so that his position wouldn't be given away. Shigaraki's appetite for destruction even eclipses his master's.
6 Kaguya Hated Humanity For What They Did To Her
Naruto
Like most Naruto villains, Kaguya was initially quite reasonable during her first foray on Earth. However, after being betrayed by her human lord, she developed an intense hatred for mortals and conspired against them. After being unsealed by Zetsu, it was impossible for Naruto or Sasuke to reason with Kaguya.
She was so committed to reclaiming her chakra that nothing they could have said would have changed her mind. Considering Kaguya's role in turning the boys against each other, they also weren't personally invested in her redemption.
5 Tonpa's Only Drive Was To Watch Others Fail
Hunter X Hunter
Hunter X Hunter's Tonpa was surprisingly difficult to reason with despite being one of the series' weakest villains. He only joined the Hunter Exam to help rookies fail, which is almost impressive considering how difficult it is to find year after year.
During the tower trial, Tonpa deliberately made it so that the heroes would have the worst odds possible. He felt no actual sympathy for Gon's plight and could not be threatened by Leorio. All he wanted was to be a malevolent man.
4 Nnoitra Wouldn't Let His Enemies Spare Him
Bleach
Although Bleach's Nnoitra was relatively well put together, he got intensively jealous of anyone better than him. His insecurities became so problematic that they even resulted in Nelliel getting ejected from the Espada organization.
During Nnoitra's fight with Kenpachi, he refused to accept defeat despite the shinigami clearly outclassing him. He was so determined to fight that he goaded Kenpachi into finishing him off. Ultimately, Nnoitra would rather die than live with the knowledge that someone was a superior fighter to him. His shame got him killed.
3 Yoshikage Kira Refused To Stop Killing
JoJo's Bizarre Adventure
After escaping from Josuke and his friends the first time, Yoshikage Kira had a rare chance to fade into anonymity. This would've made him the first JoJo's Bizarre Adventure main antagonist to get away with his crimes successfully.
However, Kira could not hide from his nature or addictions. Although successfully infiltrating a Morioh family, it wasn't long before he went back to his old ways. Eventually, Kira even planned to kill his "wife" when convinced that enough heat was off of him.
2 Death Fed On The Demise Of Others
Castlevania
Castlevania's Death cannot be reasoned with by his own nature. As an unfathomably malevolent entity from a different realm, he feeds off the end of mortal souls and endeavors to cause as many kills as possible. To this end, Death proved even more difficult to bargain with than Dracula.
At least the vampire showed restraint when dueling his son and remembering his wife. Unfortunately for Belmont and his allies, Death had no such reservations and fought him with his full, unrelenting might. It's a miracle that Belmont survived their fateful encounter.
1 Hody Jones Was A Violent Racist
One Piece
During the climax of the war for Fish-Man Island, Neptune's sons asked Hody Jones what humans did to make him hate them so much. His answer was chilling and memorable - "absolutely nothing." Instead of suffering from humans directly, Hody was indoctrinated by other fish-men like Arlong into waging his campaign against the surface world.
Considering that he has spent his entire life believing that humans deserved to die, there likely isn't a character in One Piece who could have dissuaded him from his depraved mission. Hody's radicalism makes him one of the series' most realistic albeit unreasonable villains.