Akame ga Kill! follows the story of a group of assassins known as Night Raid, who are on a mission to overthrow the corrupt government of the Empire. The main antagonist of the series is Esdeath, one of the most powerful and feared generals of the Empire. Her long, flowing blue hair is a symbol of her icy and ruthless nature. Esdeath is not only a skilled warrior, but she also possesses the power of ice manipulation, making her a formidable opponent. She is known for her sadistic tendencies, often torturing and killing her enemies without hesitation. Her bold and confident personality makes her a captivating villain to watch in action.1. "Akame ga Kill!"
In the world of Fate/stay night: Unlimited Blade Works, powerful mages known as "Masters" summon heroic spirits called "Servants" to fight in a battle for the Holy Grail. The blue-haired villain in this series is Caster, who is one of the Servants summoned by a Master seeking the Grail. Caster is a powerful mage who wields dark magic and is known for her cunning and manipulative nature. Her blue hair is a stark contrast to her all-black attire, adding to her mysterious and enigmatic aura. She is a ruthless enemy, willing to do whatever it takes to achieve her goals and claim the Grail for herself.2. "Fate/stay night: Unlimited Blade Works"
Code Geass: Lelouch of the Rebellion is set in an alternate reality where the Holy Britannian Empire has conquered Japan. The main antagonist of the series is Lelouch's childhood friend and Britannian princess, Euphemia li Britannia. Her striking blue hair and gentle demeanor hide her true intentions as she becomes the Governor of Area 11 (formerly Japan) and begins a campaign to eradicate all Japanese people. Euphemia's twisted sense of justice and her willingness to sacrifice innocent lives for her cause make her a complex and compelling antagonist. Her tragic fate only adds to the impact of her character in the series.3. "Code Geass: Lelouch of the Rebellion"
In the world of Kill la Kill, clothing is a source of power and the main antagonist, Satsuki Kiryuin, is the student council president of Honnouji Academy, a school with a strict hierarchy based on clothing hierarchy. Her blue hair and fierce determination make her a formidable opponent as she aims to rule the world with her elite group of followers known as the Elite Four. Satsuki's cold and calculating nature is often contrasted by her warm relationship with her younger sister, Ryuko. Her character development throughout the series adds depth and complexity to her role as the main villain.4. "Kill la Kill"
In the world of Black Butler, Ciel Phantomhive is the young master of a noble family and the head of a successful toy company. His blue-haired nemesis, Alois Trancy, is a wealthy young earl with a troubled past and a thirst for revenge against Ciel. Alois' blue hair is a symbol of his twisted and unstable mind as he manipulates and harms those around him in his pursuit of vengeance. His unsettling presence and disturbing actions make him a memorable and intriguing villain in the series.5. "Black Butler"
In the world of No Game No Life, gaming is everything and the fate of the world is decided through various games. The main antagonist of the series is the blue-haired goddess, Tet, who is the god of games and the ruler of Disboard. Tet's blue hair and childlike appearance may deceive some, but she is a powerful and cunning deity who enjoys manipulating and toying with the lives of humans. Her role as the ultimate antagonist in the series adds an intense and exciting element to the story.6. "No Game No Life"
Overlord follows the story of Momonga, a powerful wizard who is transported to a fantasy world after his favorite online game shuts down. The main antagonist of the series is Albedo, a beautiful blue-haired NPC (non-player character) who becomes the leader of the Guardians, a group of powerful NPCs serving Momonga. Albedo's loyalty and devotion to Momonga are unquestionable, but her intense love for him borders on obsession, leading her to make questionable and dangerous decisions. Her blue hair is a reflection of her unwavering loyalty to Momonga and her fierce determination to protect him at all costs.7. "Overlord"
In Re:Zero − Starting Life in Another World, Subaru Natsuki is transported to a fantasy world where he has the ability to return to a specific point in time after dying. The main antagonist of the series is the blue-haired witch, Satella, who is infamously known as the "Jealous Witch." Satella's blue hair and striking appearance make her stand out as a powerful and mysterious character. Her obsession with Subaru and her destructive powers make her a formidable and intriguing villain to watch out for in the series.8. "Re:Zero − Starting Life in Another World"
In The Rising of the Shield Hero, Naofumi Iwatani is summoned to a fantasy world as one of the four legendary heroes, but is betrayed and treated as an outcast by the kingdom. The main antagonist of the series is the Princess of Melromarc, Malty Melromarc, who falsely accuses Naofumi of a crime and turns the kingdom against him. Malty's blue hair and innocent appearance are a façade for her manipulative and deceitful nature. She is a skilled liar and manipulator, using her position as a princess to further her own selfish desires. Her role as the main villain adds a sense of betrayal and injustice to the story.9. "The Rising of the Shield Hero"
In Demon Slayer: Kimetsu no Yaiba, Tanjiro Kamado's family is brutally murdered by demons, leaving only his sister, Nezuko, as a survivor. The main antagonist of the series is Kibutsuji Muzan, the first demon and creator of all other demons. Muzan's blue hair is a stark contrast to his pale skin and red eyes, making him a haunting and terrifying figure. He is a master manipulator, using his power and influence to control and create more demons, making him a formidable and dangerous enemy for Tanjiro and the other demon slayers.10. "Demon Slayer: Kimetsu no Yaiba"