Akame (Akame Ga Kill!) is a deadly assassin with her skills and equally deadly Muramasa Sword.
Kurome (Akame Ga Kill!) is a deadly assassin, with drugs and experiments inserted into her body and her dead-controlling sword, Yatsufusa.
A seasoned assassin, Chelsea (Akame Ga Kill!) used her "Gaea Foundation" to transform herself, and then swiftly stab her unsuspecting target in a vital spot.
Korosensei (Assassination Classroom) is a master assassin, once known as the God of Death.
A legendary shinobi of the highest caliber, Gabimaru (Hell’s Paradise: Jigokuraku)...
...uses his Iwagakure Ninpo techniques...
...and inhuman skill to assassinate his targets with deadly efficiency.
As the Commander-in-Chief of the Onmitsukidō, Suì-Fēng (Bleach) is one of the foremost masters in the art of assassination.
Both Urahara Kisuke and Shihōin Yoruichi (Bleach) were formerly in the Onmitsukidō, as Yoruichi was the former commander in chief, and Urahara her lieutenant, and are masterful assassins.
Sosuke Aizen (Bleach) assassinated all the members of Central 46.
Haruto (Code:Breaker) is a very powerful assassin even before acquiring his powers, having a success rate of 99.9%.
As the world's greatest assassin, Mercenary Tao Tao Pai (Dragon Ball) is such a skilled killer that he can kill people using only his tongue...
...and after becoming a cyborg, Tao has eschewed the honor of a martial artist to truly devote his efforts to kill his targets at all cost.
The members of Trinity Raven (Fairy Tail) are the strongest of the Assassins in the Death's Head Caucus guild.
Jacob Lessio (Fairy Tail) is a genuine master of Magical Assassination, and one of the Spriggan 12 which makes him all the more dangerous.
Nicknamed the Bastard Child of the Death God, Mukuro, later known as Nobume Imai (Gintama) was trained by Tenshoin Naraku as an assassin from childhood, and her skills were so deadly that she was named as one of the Three Wings of Naraku.
As the leader of the Tenshoin Naraku, Oboro (Gintama) was considered to be the strongest assassin within the group, with his mastery of Hakkei and acupuncture needles to back up his reputation.
Regardless of his changing personalities, Utsuro (Gintama) is the founding leader of the Tenshoin Naraku, having 500 years of experience in killing in that he could end any life except his own.
Hitsugi (Gintama) is one of the Three Wings of Naraku, and became the last leader of the organization upon Utsuro and Oboro's demises.
The Zoldyck Family (Hunter X Hunter) is the top assassin group in the known world.
Killua Zolodyck (Hunter X Hunter) can use techniques to assassinate.
Tadashi Usobuki (Impossibility Defense) is a deadly assassin who specializes in hypnotic suggestions strong enough to actually cause his victims to die, leaving no evidence of his involvements.
Kisame Hoshigaki (Naruto) was an assassin of the Kirigakure, and would kill even his own comrades to protect what he deems important.
Zabuza Momochi (Naruto) was one of the most infamous assassins of the Kirigakure, as his Silent Killing, especially combined with Hiding in the Mist technique, was second to none.
In his younger years, Kakashi Hatake (Naruto) was once an assassin working as an ANBU.
An assassin for the Root organization, Sai (Naruto) is said to be the strongest of his generation, going as far as to eliminate his emotions.
In her own words, Nico Robin (One Piece) is skilled in assassination...
...using her mastery over her Hana Hana no Mi powers to restrain her target's movements.
The strongest of his generation, Rob Lucci (One Piece) was the greatest assassin in the history of CP9 and has served as the World Government's greatest killing machine since the tender age of 13.
The third strongest assassin of CP9, Jabra's (One Piece) skills as a Six Powers/Rokushiki master along with his Iron Body/Tekkai Kenpo makes him one of the deadliest assassins for the World Government
The Vinsmoke Family (One Piece) has a reputation within the criminal world for being a family of professional assassins.
Shuzen Akua (Rosario + Vampire) is the assassin of the Fairy Tales, and formerly of the Miao Family.
Golden Darkness (To Love-Ru) is a legendary intergalactic assassin.
Due to his fame, Younger Toguro (Yu Yu Hakusho) has been hired by many as an assassin.
Elder Toguro (Yu Yu Hakusho) was often hired by many as an assassin due to his fame.
A descendant of legendary assassins known as the Shiyuu
, a clan infamous for their bizarre and unique forms of swordsmanship
, Kyou Kai (Kingdom) is reputed to be the strongest of her generation...
...silently appearing in front of her targets before they can even notice her...
...and dispatch skilled tracking scouts with her Dancing Step
As his lord, Ren Pa's Flying Spear, Rin Ko (Kingdom) demonstrates his skills as an assassin...
...dispatching strategically important and valuable 1000-man commanders.
Since his days of fighting the Xiongnu on the border of Ganmon, Ri Boku (Kingdom) will wait for the right moment when his opponents are vulnerable to completely surprise them with deadly assassination.
Risotto Nero (JoJo's Bizarre Adventure Part V/5: Golden Wind/Vento Aureo)
The Egypt 9 Glory Gods (JoJo's Bizarre Adventure Part III: Stardust Crusaders)
Even without his Stand, Sex Pistols, Guido Mista's (JoJo's Bizarre Adventure Part V/5: Golden Wind/Vento Aureo) uncanny precision with a revolver and ability to keep cool even in the middle of a gunfight makes him a deadly assassin.
La Squadra Esecuzioni/Hitman Team (JoJo's Bizarre Adventure Part V/5: Golden Wind/Vento Aureo) specialize in Stand related assassinations.
Cioccolata & Secco (JoJo's Bizarre Adventure Part V/5: Golden Wind/Vento Aureo)
Out of all the Trinity Seven, Levi Kazama (Trinity Seven) has killed most during her assassination missions, and achieved perfect success rate in both missions and assassinations.
Sham Lash (Magi The Labyrinth of Magic) the Parthevian Empire secret assassination squad.
As the leader of the Sham Lash, Shaka (Magi The Labyrinth of Magic) is a dangerous master assassin, able to massacre countless people by himself...
...and kills a Household Vessel Assimilated Giant Monster with a single ki-infused attack.
Jafar (Magi The Labyrinth of Magic) is a child prodigy in the assassination, having once been one of Sham Lash's most elite assassins at 10 years old.
Goblin Slayer (Goblin Slayer) uses and employs various assassination tactics in killing goblins.
A top-notch sniper of the highest caliber, Duke Togo (Golgo 13) is the world's greatest hitman and assassin.
Kang Tae-Shik (Solo Leveling), a B Rank Assassin Class Hunter.
Despite his Mage Class, Sung Jin-Woo (Solo Leveling) has the stealth and speed of an Assassin, in addition to his usage of daggers.