The CW's Arrow follows the rise and fall of Oliver Queen (Stephen Amell). Throughout the show, Oliver has remained fiercely intent on helping people. Even so, there have been many occasions where Oliver steps far across the line in that noble pursuit of justice.

RELATED: Arrow Creator Shares Original Pitch Notes Featuring Character We Never Met

There are times where he dips so far into this internal darkness that it is not too much of a leap to say that he has, often, embodied the villain, rather than the hero.

Here are Oliver's 10 greatest moments of cruelty and evil.

Leaving Alan Durand To Die

In the Season One flashbacks, Oliver Queen, a spoiled playboy, was overcome by paralyzing terror at finding himself alone on Lian Yu. But that quickly changes. After a failed attack on Edward Fyers' base, Slade Wilson is desperately injured. Oliver returns to Yao Fei's cave to retrieve medicine for Slade. There, he discovers a man, bound and beaten, who claims to have barely survived the soldiers and begs Oliver to help him. The conflict shows clearly on Oliver's face. He is about to cut the man free when he pulls the knife back.

"I can't," he says, "because I don't know you."

RELATED: 'Arrow' Star Explains Why Oliver Queen Is A Killer

This doesn't seem like the kind of behavior a self-purported 'hero' would have. Regardless of the fact that Durand was, indeed, working with Fyers, this was the first time that Oliver's naive heart began to harden. Survival, paranoia, these are the constants in his life.

Killing Edward Fyers

In the final flashback of Season One, Oliver is standing, just feet from the defeated Fyers, who has a gun pressed to Shado's head. Oliver aims for Fyers' throat, and releases his arrow, killing him instantly. While this could be explained away as a hostage situation, a situation in which he didn't have another choice, it is in his reaction to this kill that his cruelty shines. This kill did not occur in the midst of battle; it was not fast-paced, it was deliberate. And his eyes, those windows into the soul, remain entirely unmoved by the life he just took. This moment, that decision to shoot instead of allowing one of his companions to rescue Shado, is one that ultimately sets him upon a terrible path, establishing the 'monster' within that plagues Oliver for the length of his vigilante career.

The Concept and Collateral of His Crusade

When Oliver at last returns from his 5-year stint abroad, he is a hardened killer and a great warrior. He comes back with one mission: to right the wrongs of his father, through the medium of 'the list,' a little book with the names of all the men who are oppressing the people of Starling City. To Oliver, the crossing-off of a name equals the killing of that person. The whole idea of this aligns closer to the dark side of things than the light. Regardless of the sins of his targets, the idea that he can act as judge, jury, and executioner is in violation of basic human values. That aside, the collateral of this crusade is often ignored. In Season One alone, Oliver kills 55 people - many of these are the security forces who exist to protect his high-value targets. Barring mob-related activity, these men are security guards - with families and lives - who are just doing their jobs. Yet Oliver takes it upon himself to shoot to kill every time he goes to cross another name off the list.

Attacking the Guards in Prison

In the seventh season, on his quest to hunt down Ricardo Diaz, Oliver Queen stumbles into a fight club of sorts. He beats his opponent, Sampson, and then scales the wall, holding a shiv to Brick's throat. A handful of corrupt guards have their weapons trained on him, but Oliver is determined and desperate.

RELATED: The 15 Most Powerful Arrowverse Heroes, Ranked

In order to find Ricardo Diaz, he must get sent to level two. So, Oliver stabs the guards. Not the cruelest thing he has ever done, yet still, his focus on his own mission, his own personal vendetta, leaves a lot of collateral.

Murdering A Lian Yu Soldier

Some of the first flashbacks of Season Two reveal that Oliver, Shado, and Slade have remained stranded on the Island. When a proximity detector reveals that three armed men are nearby, the companions go to check it out, but Shado is captured, and Oliver and Slade set out to rescue her. When they finally make their move, Oliver focuses on the man who was questioning Shado and knocks him to the ground where he begins to beat him ruthlessly. Oliver, in a blind rage, lifts a stone from the ground and bashes the soldier's skull in repeatedly; ignorant to the cries of his friends to stop. This is not killing for survival, this is the kind of killing that one does when they enjoy it.

'Killing' Slade Wilson

At the end of the Season Two flashbacks, Slade Wilson becomes revenge-crazed by the Mirakuru, a drug that enhanced his strength. During their final duel, the boat begins to break apart, and Slade is trapped by a massive cross-section of the ship, leaving him helpless. On one hand, Oliver holds the cure to the drug, in the other, he holds an arrow. He stands there, contemplating, listening to Slade's incendiary words, and lunges forward, slamming the arrow deep into Slade's eye. If Oliver's soul was unblemished, he would have saved his friend, rather than allow his own rage and blood lust to consume him.

Torturing a Member of the Chinese Triad

Season Three flashbacks find Oliver working for Amanda Waller and Argus, in Hong Kong. "Torture is an art form," she tells him, "I think you not only have the stomach for it, you have the talent." When Oliver is at first reluctant, and unable, to extract information from a triad member via torture, Waller gives him a second chance. When he finally breaks and agrees to torture this man, all that is shown is an ominous un-zipping of his duffel bag, revealing a quiver full of arrows. It is safe to assume that Oliver then goes through with it. Torture definitely falls under the umbrella of acts of villainous cruelty.

Attacking the Inmates in Prison

In the Seventh Season, Oliver Queen is in jail and trying to come to terms with the fact that, for once, he has to keep his head down. After enduring an endless amount of abuse, he finally snaps, picks up a book, and walks into the weight area of the prison. He smashes the book into one inmate's throat, then picks up a clearly metal weight plate, and proceeds to use the weight plate to brutally beat another inmate. Here is a man who enjoys killing and the feeling of power it grants him.

Torturing General Shrieve

Oliver pursues and tortures general Shrieve

In the final flashback and episode of Season Three, Oliver has captured General Shrieve, the man behind the sweeping attacks that have struck the city. The General is bound and has no information that might help Oliver. Nonetheless, he nocks an arrow to his bow. When next we see him, the General is lying on the ground, covered in blood, with half-a-dozen arrows embedded in his still-breathing corpse. This is proof that Oliver has mastered the art of torture, and that performing torture makes him feel good. He is no hero.

Skinning A Russian Agent Alive

The Season Five flashbacks reveal a hardened Oliver, one that has become indoctrinated into the Russian brotherhood that is the Bratva. Seeking information about Kovar's impending gas attacks, he captures one of Kovar's men, blindfolds him, and ties him to a table. "Please, I don't know anything," he says, as Oliver sharpens his knife. "A friend of mine recently showed me a skinning technique used by hunters in Mongolia. They remove all the skin of things much larger than you...in less than five minutes. Which means you don't have very long to tell me what your boss is planning." As the man persists that he knows nothing, Oliver says: "I was kind of hoping you'd say that."

Then, the screaming begins.

NEXT: Arrowverse Theory: Earth-2 Destruction Really Was Oliver Queen's Fault