Hero Killer Stain's (My Hero Academia) desire to kill "fake heroes" can frighten even the most experienced of heroes with his aura alone.
Esdeath (Akame ga Kill) is terrifying and murderous sadist who enjoyed most brutal battles and ending people's lives in the most agonizing ways.
Despite his initial character, impression and appearance, Nagisa Shiota (Ansatsu Kyōshitsu) possesses a frighteningly massive amount of hidden bloodlust.
Guts (Berserk) knows solace through fighting and killing as many enemies as possible. At one point, his need to fight was enough to drive him to kill one hundred Chuder soldiers in a single night...
... and after the events of the Eclipse his need to kill manifested The Beast of Darkness that urges him to continue on killing every last Apostle and revenge against the Godhand.
When taken over by his inner Hollow, Ichigo Kurosaki (Bleach) becomes a nigh-unstoppable killing machine.
According to Yhwach, the First Captains of the Gotei 13 (Bleach) were actually a brutal mob of killers.
Genryusai Yamamoto (Bleach) was once feared as a demon due to his ruthless leadership who even sacrificed his own subordinates and innocent lives to fufilled his goals.
Yachiru Unohana (Bleach) was feared as the most terrifying criminal of Soul Society due to her endless thirst for bloody battle.
Yhwach (Bleach) is the merciless leader of the Quincies who will readily sacrificed anyone to the point of commiting patricide by absorbing the Soul King to realize his goals.
Rei Ogami (Code:Breaker) ruthlessly killing evil while ignoring all pleas.
Tyki Mikk (D.Gray-man) awakens, which instills in him a single-minded desire to kill Exorcists.
Upon becoming a Super Saiyan 2, Son Gohan (Dragon Ball) became a merciless, sadistic killer who deliberately dragged out his fight with Cell to torture him.
Kid Buu (Dragon Ball) is a near-mindless killing machine who cares for nothing but wanton mass destruction. If he is not destroyed, Buu will not stop until everything in existence is wiped out.
While she has blue hair, Launch (Dragon Ball) is sweet and gentle. However whenever she sneezes, her hair turns blonde and Launch becomes a vicious psychopath.
Broly (Dragon Ball Z) is destructive, drove by Goku/Kakarot when they were infants.
Lucy (Elfen Lied) is the Diclonius meant killing humans, drove by DNA Voice.
Acnologia (Fairy Tail) is an extremely ruthless Dragon Slayer, having slaughtered countless Dragons to satisfy his thirst for revenge.
Utsuro (Gintama) has suffered persecution for centuries due to his immortality, and has developed multiple personalities that turned to serial killers and cold-blooded assassins, and the original Utsuro has became omnicidal.
Goblin Slayer (Goblin Slayer) is completely ruthless in hunting down goblins, to the point of massacring any goblins nest he can find...
Inuyasha (InuYasha), when overcome by his demon blood, has a tremendously murderous intent.
Despite his stern, no-nonsense exterior, Kars (JoJo's Bizarre Adventure Part II Battle Tendency) possesses a murderous and sadistic nature…
…massacring most of his race, including his parents when they sought to execute him in order to maintain natural order.
DIO (JoJo's Bizarre Adventure) shows a lack of restraint in his violence, and is prone to murderous outbursts even as far as his childhood.
Yoshikage Kira (JoJo's Bizarre Adventure Part IV Diamonds are Unbreakable) is a paraphilic serial killer who has been lurking unnoticed in the town of Morioh for years.
Possibly mimicking his father's tendency, Giorno Giovana (JoJo's Bizarre Adventure Part V Vento Aureo) has shown his ability to kill when it's absolutely necessary or the last resort.
Before becoming a general for the Qin, Kan Ki (Kingdom) was a mountain bandit with a penchant for decapitation as he would personally behead every person in any city or village he conquered, which earned him the moniker the Beheader.
Due to his father corrupt teachings, Felix Aaron Thenardier (Madan no Ou to Vanadis)…
…grew up to become an extremely ruthless and brutal tyrant.
Driven insane by her hatred for King Solomon, Arba (Magi the Labyrinth of Magic) became immensely sadistic and brutal willingly to kill even her own descendants for both world annhilation and sadistic entertainment.
As a creature born from evil energy, Orb (Marchen Awakens Romance) will kill anyone he wants without even a remote sense of remorse.
Influenced by the Orb, Diana (Marchen Awakens Romance) has grown into a power-hungry woman who will show no mercy to those who stand in her way of becoming the queen of MÄR Heaven.
Despite his charms, Phantom (Marchen Awakens Romance) is the mad leader of the evil Chess Pieces army, who accepted the Zombie Tattoo to become immortal. Looking down on the mortality of the world, Phantom will stop at nothing to wipe out all of humanity.
While under the influence of the Zombie Tattoo, Alviss (Marchen Awakens Romance) entered a berserk state where he wouldn't hesitate to kill his own allies.
Peta (Marchen Awakens Romance) shares Phantom’s ideals that humans are trash and feels no regret for the pain he causes others. He once even wiped out an entire fortress, not only killing enemy warriors, but innocent women and children as well.
After killing the ones who constantly bullied him as a child, Halloween (Marchen Awakens Romance) learned the pleasure of tormenting others. He grew up to join the Chess Pieces as one of their strongest and most sadistic soldiers.
After acquiring the power to get revenge on the men who tortured her, Chimera (Marchen Awakens Romance) decided to abandon her humanity as well as her original name, Eileen. Becoming known as Chimera, a monster who enjoys giving pain rather than receiving it.
Weasel’s (Marchen Awakens Romance) Guardian ÄRM, Yggdrasil is a tree that grows by absorbing the pain and suffering her master causes others.
Candice (Marchen Awakens Romance) was a sadistic army commander who showed no mercy in battle. Her bloodlust only increased when she defected to join the evil Chess Pieces.
When Rapunzel and Girom’s (Marchen Awakens Romance) father died of a disease, their mother became demented. She denied them of everything, even food and whipped them each day. This abuse would later seep into the siblings giving them sadistic personalities.
Because of his ugly face, Kouga (Marchen Awakens Romance) has been treated miserably ever since he was a boy. The abuse and humiliation drove him into madness. Ever since he joined the Chess Pieces he's had a tendency to kill those around him, especially handsome boys.
Pinocchion (Marchen Awakens Romance) is a doll brought to life with dark magic. In addition to being a liar, Pinocchion is a sociopath who won't hesitate to kill to impress the Chess Pieces' Queen.
Orco (Marchen Awakens Romance) is a simpleminded but sadistic Bishop class Chess Piece. He takes pleasure in destroying buildings and along with Girom, was the one who demolished the beautiful city of Vestry.
Maira (Marchen Awakens Romance) was once nothing but a cowardly Pawn-class Chess Piece. One day however he discovered Vaqua, a Guardian ÄRM with the power to absorb others. Since then, Maira has found pleasure in using Vaqua to absorb as many people as possible.
Of all the psychopaths who converged towards the Chess Pieces' banner, the Zonnens (Marchen Awakens Romance) stood out as perfect examples of barbarity. Enjoying the era of chaos, they indulged in abominable acts of abduction, decimation and destruction and beheld the ravage as a sight of beauty. Because of their savagery, even Phantom revolted their very presence.
Saturn (Marchen Awakens Romance) is the leader of the barbaric Zonnens. Despite his Rook earring, Saturn possesses both the power and viciousness of a Knight-class Chess Piece. He even considers being called a monster as a compliment and prefers to torture his opponents before he kills them.
Kei Munakata's (Medaka Box) Abnormality is his instinctive desire to kill. His instinctual ability as a killer is so great that he is capable of inflicting fatal injuries with his bare hands.
As a child who wasn't old to be a ninja yet, Zabuza Momochi (Naruto) slaughtered over 100 Academy students without pause or hesitation later earning the title of a Demon.
Before being defeated by Naruto, Gaara (Naruto) was a near psychotic killer, especially when Shukaku influenced him.
Shukaku (Naruto) is a very bloodthirsty monster tanuki, and even more so when under the full moon.
The now extinct Kaguya Clan (Naruto) were known for their savagery and lust for bloodshed and war.
Deranged with revenge, Sasuke Uchiha (Naruto) becomes a completely amoral murderer.
When his enzymes take over, Jūgo (Naruto) becomes temporarily insane with killing intent.
When Shiliew of the Rain (One Piece) was the Head Jailer of Impel Down, he ruthlessly killed any prisoner he wanted.
Sakazuki/Akainu (One Piece) is the Fleet Admiral of the Marines, deeply feared by both pirates and marines alike due to his complete ruthlessness in serving justice.
When Arlong (One Piece) is angry, he enters a killing mode of sort, befitting that of a shark.
Hody Jones (One Piece) inherited the fishman's hatred for humanity since he was taught to do so. He and his crew harm their minions and the ones who are friendly to humans.
Donquixote Doflamingo (One Piece) is sadistic tyrant described by his own brother as a demon who was born evil. Due to childhood trauma, he swore revenge against the Celestial Dragons by destroying the world they ruled over, massacring countless people including Dressrossa citizens and his own father and brother.
Caesar Clown (One Piece) is a mad scientist with a reputation of building weapons to murder people and no problem killing his own henchmen just to demonstrate his inventions.
Pica (One Piece) is very sensitive about his high-pitched voice. If someone so much as snickers, Pica will violently slaughter them.
Due to being constantly ridiculed during his years as a slave, Gild Tesoro (One Piece: Flim Gold) will kill anyone who dares to laugh without his permission.
Despite his flamboyant and flashy attitude, Dellinger (One Piece) becomes sadistic and bloodthirsty because of his own heritage of Fighting Fish fishman.
Gladius (One Piece) is feared for his very short temper which often gets the best of him. If someone offends him or his captain, Doflamingo in even the slightest way Gladius will use his powers to blow them up.
Caribou (One Piece) is an insane pirate known for slaughtering Marines. His sadistic nature leads to him using brutal ways to kill people such as burying them alive or suffocating them with his powers.
Cavendish (One Piece) possesses a dual personality, Hakuba, who is ruthless in slashing down everyone in range whenever Cavendish falls asleep.
"Big Mom" Charlotte Linlin (One Piece) is immensely brutal, she will ruthlessly kill anyone even her own children. What she desires above all is sweets and will destroy entire countries should they fail to give it to her. Invitees who refused to attend her tea parties will have their loved ones decapitated as presents.
Due to Linlin's influence, most of the Charlotte Family (One Piece) are just as murderous and ruthless as their tyrannical mother.
Charlotte Perosperos (One Piece) is one of the most sadistic members of the Charlotte Family. He even cannibalize people by turning them into candy.
Charlotte Katakuri (One Piece) is fiercely loyal to his mother Linlin and is willing to ruthlessly kill to realize her goals.
Charlotte Brulee (One Piece) enjoys killing and disfiguring attractive girls.
Charlotte Amande (One Piece) believes there is no meaning in slaughter if the victims can't experience the pain. Demonstrating as she slowly sliced KingBaum, giving the giant tree an agonizing death.
Being viciously bullied and scorned for her third eye as a child Charlotte Pudding (One Piece)…
…grew up to be very cruel and sadistic.
The Vinsmoke Family (One Piece) are a royal family of prestigious Underworld assassins and mercenaries.
Don Krieg (One Piece) is a ruthless pirate admiral known for his underhanded tactics and mass murders. His dishonesty and brutal nature earned him the alias "Foul Play Krieg".
Kaido (One Piece) is a ruthless warrior who does not make himself open to negotiation or excuses and won't hesitate to kill should someone fail to comply with his demands.
Jack the Drought (One Piece) has an unreasonable nature and always resorts to bloodshed, including to attacking children and the elderly and has a love for causing destruction, even when there is no real benefit to it.
Rob Lucci (One Piece) is a heartless mass murderer and the strongest member in the history of CP9…
…and at the age of 13, slaughtered 500 kingdom soldiers for surrendering to pirates.
Thinking of himself as God because of his Logia Devil Fruit powers, Enel (One Piece) believes he has the right to kill anyone he wants and is one of the most sadistic, egotistical, and uncaring characters of the series. He even destroyed his entire home, Birkia just because he felt like it.
Kuro (One Piece) shows absolutely no remorse in killing his subordinates.
A bloodthirsty psychopath, Capone Luke "Gang" Bege (One Piece) is infamous in the Underworld for attacking mafia leaders simply for the sake of causing blood smeared chaos. His lust for bloodshed is so extreme, that he even desires to assassinate the Yonko Big Mom.
The Deep Sea King (One-Punch Man) is a sadist who enjoys causing pain to others and starting fights.
Zahlenschwestern (Phantom of Inferno) are elite brainwashed female assassins of scythe master. They were created using the fighting data of Ein, Zwei and Dre…
…Zwei and Ein were taken by scythe master because of their natural killing instincts. They were brainwashed and trained to eliminate any threat to inferno. Zwei's eye color change when his killer instincts are activated.
Akua Shuzen (Rosario + Vampire) giving her signature deranged look that is filled with killing intent.
Giriko (Soul Eater) can overwhelm his opponents with sheer raw power of the blood-lust built up over 800 years.
Maruss (Zatch Bell!) is a short tempered mamodo who finds pleasure in taking his anger out on innocent people. Due to Tia getting away from him so many times, he threatened that once he burned her book he would attack her bookkeeper's concert.
Zofis (Zatch Bell!) is a heartless mamodo who only cares about becoming king. After brainwashing the sweet Koko into becoming his bookkeeper, Zofis forced her to burn down her village.
Koko (Zatch Bell!) became sadistic because of Zofis' mind control and enjoys hurting people just as much as her mamodo does.
Clear Note (Zatch Bell!) believes killing mamodo is the very reason for his birth and only wants to become king so he can bring genocide upon his people.
Despite being an infant, Clear Note's bookkeeper, Vino (Zatch Bell!) enjoys helping his mamodo and gets sadistic pleasure in hurting people and mamodo alike.