The grim, solitary life of an assassin has been explored in movies for decades, resulting in some of the most arresting characters to ever stalk across the silver screen. They are sometimes heroes, sometimes anti-heroes and sometimes villains, but the figure of the relentless killer-for-hire can transcend genres and can often place a movie’s moral or theme in a key context or contrast.

The upcoming Hitman: Agent 47 is based on the hit video game series and is a second attempt to spin the saga of the bald, genetically-engineered killing machine Agent 47 into a viable film franchise. To coincide with the movie’s release, here are the 10 Most Ruthlessly Efficient Movie Assassins of all time.

Martin Blank (Grosse Pointe Blank)

John Cusack relaxes with a gun in his hand from Grosse Pointe Blank

George Armitage – a veteran B-movie director also responsible for a blaxploitation flick from 1972 called Hit Man – helms this dark comedy about the jaded hired assassin Martin Q. Blank (John Cusack), something of a wunderkind among the admittedly small community of hit men and when we meet him is being actively recruited by fellow killer for hire Grocer (Dan Ackroyd) to join a hit man union of sorts.

Martin returns to his hometown of Grosse Pointe, Michigan for his ten year high school reunion, reunites with his lost love Debi (Minnie Driver) and eventually comes to realize that he has apparently grown a conscience over the years and has lost his taste for killing. This doesn't stop him from efficiently dispatching another killer (Benny Urquidez) hired by a vengeful millionaire, a couple of rogue NSA agents (Hank Azaria and K. Todd Freeman) and the lunatic Grocer himself along the way.

Mystique (X-Men Trilogy)

Mystique in X-Men

Before X-Men fans were reintroduced to a younger Raven Darkholme/Mystique in the form of Jennifer Lawrence in X-Men: First Class, Rebecca Romijn (previously known as Rebecca Romijn-Stamos) portrayed the deadly shape-shifting mutant in the original trilogy of films.

Uncompromising and fiercely devoted to the villain Magneto (Ian McKellan), the first cinematic version of Mystique lacks any kind of backstory, making her all the more terrifying. Capable of impersonating anyone at all and able to perform gymnastic feats of mayhem, Mystique easily infiltrates the inner circle of anti-mutant Senator Kelly (Bruce Davison) killing his bodyguard and eventually taking his place - evidently, doubling as a United States senator is all part of the gig.

Mystique is essentially Magneto's fanaticism in action - at least in the original X-Men films. The quasi-reboot Days of Future Past presented a much more conflicted character, but her ruthless and exacting skills are still very much on display.

Léon (Léon: The Professional)

Leon and Mathilda in The Professional

Another example of a killer with a conscience, Léon (known as The Professional to American audiences during its initial theatrical run) from director Luc Besson follows the eponymous hired assassin, whose rigorous and solitary lifestyle is disrupted by a young girl named Mathilda (Natalie Portman, in one of the most striking film debuts of all time).

Orphaned after the brutal murder of her parents by the insane corrupt cop Stansfield (Gary Oldman), Mathilda vows revenge and demands training in the ways of "cleaning" from Léon. As played by Jean Reno, Léon is something of a gentle, isolated soul who proves to be an effective father figure for Mathilda even as he wipes out Stansfield's criminal organization. Léon slaughters the army of thugs without remorse, their existence an affront to his code of "no women, no kids."

Hit Girl (Kick-Ass, Kick-Ass 2)

Hit Girl in Kick-Ass

Based on a characteristically ultra-violent comic book series written by Mark Millar, director Matthew Vaughn's Kick-Ass was a hyper-active take on the superhero genre and starred Aaron Taylor-Johnson as a regular teenager who decides to become the titular hero despite his utter lack of skills or training.

Enter Hit Girl (Chloë Grace Moretz) and her father and mentor Big Daddy (Nicolas Cage). A former cop framed as a drug dealer by the brutal mob boss Frank D'Amico (Mark Strong), which led to his wife's suicide, Big Daddy trains his daughter (by way of point blank handgun rounds to a bulletproof vest) to become the raging, foul-mouthed vengeance-machine Hit Girl.

Hit Girl remains one of the highlights of Kick-Ass and its less well-received sequel and is an irrefutable force to be reckoned with. Grace Moretz's performance also turns out to be the original film's beating heart, even as she whips Kick-Ass into fighting shape.

Ogami Ittō (Shogun Assassin)

Ogami Itto in Shogun Assassin

Perhaps best known to modern audiences as the movie that Bill (David Carradine) lets his daughter B.B. (Perla Haney-Jardine) watch before bedtime in Quentin Tarantino's Kill Bill, Shogun Assassin is a Japanese martial arts classic released in English-speaking markets in 1980, but cut together from the Lone Wolf and Cub films from 1972.

Ogami Ittō (Zatoichi star Tomisaburo Wakayama) is a medieval Samurai and feared Decapitator for the insane, paranoid Shogun. Out of fear of Ogami, the Shogun's ninja kills the samurai's wife, forcing him to take to the road with his young son Daigorō, leaving a bloody trail of failed assassins in their wake.

From the opening encounter with two of the Shogun's assassins to the final battle against the three-brother ninja team the 'Masters of Death' - and the classic battle scenes in between -  Shogun Assassin presents Ogami as a devoted father and one of the most exacting and merciless screen killers of all time.

John Wick (John Wick)

Keanu Reeves in John Wick

Keanu Reeves seemed to reside in the wilderness, with several recent and fairly well-received projects – 47 Ronin and Man of Tai Chi, which he directed and co-starred in – failing to set the box office on fire. Then came 2014’s John Wick, a roaringly good action vehicle starring Reeves as the eponymous retired hit man dragged back into the fray.

Having lost his wife to a terminal disease and long since given up the life of a hired assassin, John Wick is just starting to bond with Daisy, the puppy his wife left him for companionship. When his fragile peace is violated by Iosef (Game of Thrones' Alfie Allen), the spoiled son of mob boss Viggo (Michael Nyqvist), Wick avenges the death of his puppy - and by extension the memory of his wife's grace - and becomes a one man army of revenge.

As Wick, Reeves reignites memories of his days in The Matrix in what the actor has called "a kind of Old Testament revenge story,"  mowing down anyone and everyone Viggo sends his way in peak form and high style, while never losing the sense of the wounded heart that drives him.

Nikita (La Femme Nikita)

Anne Parillaud holds a gun while sitting on the ground in La Femme Nikita

Director Luc Besson's La Femme Nikita has inspired one American feature remake (Point of No Return), two different TV series adaptations, and presaged some of the more straightforward (non sci-fi or horror) female-led action thrillers to follow (Haywire, Hanna).

After homeless teen Nikita (Anne Parillaud) kills a policeman while robbing a pharmacy, the authorities fake her death and train her as an assassin. She proves herself a gifted killer, as evidenced during the now-classic scene in a high class restaurant, where the celebration dinner with her mentor "Bob" (Tchéky Karyo) turns out to be her final test: taking out a diplomat and surviving his armed security guards entirely on her own.

Nikita is yet another conflicted hired killer, and as she is psychologically tested by Bob – forced into an assassination during what she thought was a romantic getaway with her new boyfriend – she is tempted to leave her deadly calling for a normal life, which may not be possible, given her nature.

Vincent (Collateral)

Tom Cruise as Vincent in Collateral

Tom Cruise doesn't often play against type, but he can be electric when stepping outside of his more heroic, good guy roles. Case in point: his electric performance as the cold-blooded contract killer Vincent in Michael Mann's Collateral. Cruise's confident, philosophizing hit man prowls the streets of Los Angeles, having hired on cab driver Max (Jamie Foxx) to drive him around town for the night under the guise of closing a business deal. When the bodies pile up, Vincent forces Max to become a reluctant accomplice.

While Cruise earned an Oscar nomination for his similarly unsympathetic turn in Paul Thomas Anderson's Magnolia, the star is arguably in his element as Vincent. From his remorseless murder of a nightclub owner target after "bonding" over Miles Davis and efficient dispatch of two lowlifes who steal his briefcase to his scary rampage through a bar as Max attempts to slip away, Cruise's character lacks a backstory but remains a memorably vicious example of a single-minded killer's id in action.

Miho (Sin City)

Devon Aoki as Miho in Sin City

Robert Rodriguez's 2005 Sin City did not adapt legendary comic book writer/artist Frank Miller's seminal graphic novel series so much as pump it full of steroids and bring it to monstrous cinematic life. Miller and Rodriguez's hyper-noir hellscape is populated exclusively with killers, sinners, gamblers, strippers, prostitutes and psychopaths. Even the nobler characters are broken and hiding secrets, such as Bruce Willis' doomed detective, Jessica Alba's kidnap survivor turned dancer and Clive Owen as the mysterious Dwight, who runs afoul a corrupt cop (Benicio del Toro) and ends up hunted through the streets of Basin City's Old Town.

Enter Miho - played by Devon Aoki in Sin City and Jamie Chung in the sequel A Dame to Kill For - resident assassin of Old Town, which is controlled by the ladies of the streets. Miho never utters a word, is not given any kind of background and is all the more terrifying for it. She is a blank-faced force of nature, slicing through the army of goons who descend on her territory with an utter lack of empathy, exhibiting the qualities which illustrate why Frank Miller calls the character a "good demon" of Sin City.

O-Ren Ishii (Kill Bill: Vol. 1)

Lucy Liu as O-Ren in Kill Bill

While Quentin Tarantino's epic revenge saga Kill Bill revolves around Uma Thurman's tour de force performance as the Bride (a.k.a. Black Mamba, a.k.a. Beatrix Kiddo), the first name on her hit list was that of former fellow member of the Deadly Viper Assassination Squad O-Ren Ishii (Lucy Liu). In fact, O-Ren's rise to power as the boss of all the yakuza gangs in Tokyo is remarkable, considering her half-Japanese, half-Chinese-American parentage, not to mention the horrific childhood trauma which molded her into a now-legendary screen assassin.

Of all the characters in the Kill Bill saga - or this list in general - O-Ren is given the most detailed backstory, famously rendered in anime-style animation. Upon witnessing the death of her parents at the hands of Boss Matsumoto, O-Ren exacts a merciless revenge and undergoes training as an assassin, becoming one of the top killers for hire in the world by age 20.

We see how O-Ren deals with dissension in the ranks as she quickly beheads a yakuza boss who disparages her lineage and her final samurai sword duel with the Bride is one of the film's highlights. Every members of the D.V.A.S. was extremely dangerous, but in the end it seemed that only O-Ren a.k.a. Cottonmouth really gave Beatrix a run for her money.

Conclusion

These are only ten of the most ruthless and efficient screen assassins, and there are some others which deserve mention. The great Max von Sydow turned in a performance for the ages as the gentlemanly and insightful contract killer Joubert in the classic 1975 political thriller Three Days of the Condor; Jude Law scummed up his good looks to play Road to Perdition's crime photographer Harlen Maguire, who also happened to moonlight as an assassin (he got the best photos that way); Billy Connolly was a live wire in The Boondocks Saints as Il Duce ("The Duke"), a hit man tasked with taking down the brothers MacManus before the plot thickens.

Many of the assassins on our list wind up confronting demons from the past or becoming emotionally compromised at some point, but it'd be advisable to cross none of them. Will our latest incarnation of Agent 47 in Hitman face similar challenges as he completes his missions? We'll find out soon enough.

What do you think of this list of ruthless assassins, Screen Ranters? Who would you add? Sound off in the comments!

Hitman: Agent 47 opens in theaters on August 28, 2015.