As one of Lost's most prominent antagonists, Ben Linus committed some despicable acts throughout the show's run. These were his worst actions.

Initially introduced as "Henry Gale" in season 2, Ben Linus went on to become one of Lost's most important and complex characters. The show took time to humanize and redeem him, but Ben also served as a formidable antagonist for the survivors of Oceanic Flight 815.

Throughout the show, Ben committed a number of ruthless acts. The worst of those were pure evil, led to negative consequences for other characters, or were emotionally devastating for fans.

Grab a bottle of Dharma Initiative ranch dressing as we explore the 10 worst things that Ben did.

10 Not Letting Juliet Leave The Island

Juliet longed to leave the Island and see her sister Rachel again. Ben prevented her from leaving the Island every time she asked. Juliet got to see a live video feed of Rachel cured of her cancer and playing with her young son.

Ben only let Juliet watch the video feed for a few moments and despite her renewed urge to leave, he still demanded that she stay on the Island until her work was done. In reality, though, Ben had no intention of ever letting her leave.

9 Showing Off Goodwin's Corpse

Ben took sickening pleasure in showing Goodwin's corpse to Juliet. He made it clear that he knew about Juliet's affair with Goodwin and didn't deny the accusation that he purposely sent Goodwin on a suicide mission for this very reason.

To make the scene even worse, Ben revealed truly possessive and toxic behavior as he emphasized that he was showing her Goodwin's body so she could "understand that you're mine."

8 Trying To Kill Penny

Charles Widmore was responsible for the death of Ben's daughter Alex. In response, Ben promised he would kill Widmore's daughter Penny. This is wrong, to begin with, but it's even worse when considering that Penny had absolutely no relationship with her corrupt father.

Penny was a good woman finally living the peaceful life she wanted with Desmond and their child. Ben didn't care and came unnervingly close to killing her. Fortunately, Desmond managed to stop him.

7 Kidnapping Walt

Kidnapping a child is inherently despicable, no matter how "special" they may be. Ben and the Others conducted experiments on Walt in the unsettling Room 23. Not only was this ordeal terrible for Walt, but it had a devastating effect on Walt's father Michael. Walt's captivity drove Michael down a dark and desperate path, one where he betrayed his friends and even killed Ana Lucia and Libby.

Ben did make up for this some in the show's epilogue "The New Man In Charge." Ben located Walt on the mainland and sincerely apologized for what he did to him. Most importantly, Ben helped Walt escape so he could return to the place where he belonged – the Island.

6 Tormenting Kate & Sawyer To Manipulate Jack

In the early episodes of season 3, Ben and the Others relentlessly tormented Kate and Sawyer. Ben had Kate and Sawyer kept in cages and forced them to haul rocks. Sawyer was brutally beaten on several occasions and stuck with a needle against his will.

Ben engineered all of this torment just to manipulate Jack into operating on him. Ben knew Jack was the only one who could remove his cancerous tumor, but also that Jack would never save him willingly. Instead, he made life a living hell for Kate and Sawyer, which was agonizing to watch for numerous episodes.

5 Leaving Locke For Dead In A Mass Grave

Ben shot John Locke and left him for dead in a mass grave. It's a ruthless thing to do in the first place and is only made worse when the reason behind Ben's action is considered. He was jealous that Locke could seemingly hear Jacob. Ben was already bitter about dedicating his life to the Island, while also being unable to ever directly communicate with or meet Jacob. Ben felt threatened by Locke and wouldn't stand for his leadership position to be compromised with the Others.

The only reason this isn't higher on the list is that Locke managed to survive. However, it wouldn't be the last time that Ben tried to murder Locke.

4 Helping To Massacre The Dharma Initiative

In an event known as the Purge, the Others released a poisonous gas that massacred almost every member of the Dharma Initiative. Ben helped the Others carry out this atrocity, in addition to personally killing his abusive father. Ben's resentment toward his father is understandable, as is the Others' resentment toward the people who "invaded" their Island. This still doesn't justify the merciless slaughter that they carried out, which killed children and plenty of innocents who never did anything to harm the Others.

Despite the horror of this event, it isn't higher on the list because the audience lacked emotional investment in the Dharma Initiative. The Purge was shown in a season 3 flashback, but fans didn't get to know the members of the Dharma Initiative until season 5.

3 Stealing Alex From Her Mother

Ben stole Alex from her mother Danielle Rousseau. Rousseau was already in a bleak situation as she'd been forced to kill her lover and colleagues after they were "infected" and tried to kill her. She was alone, stranded on the Island, and all she had left in the world was her baby daughter.

Then Ben came along and stole the baby from her. Losing Alex drove Rousseau mad as she spiraled into a dark and paranoid state of mind. The only redeeming factor in this situation is that Ben was originally ordered to kill both the mother and daughter, but he spared their lives and took the baby instead.

2 Killing Locke

After failing to convince the Oceanic Six to return to the Island, John Locke was on the verge of committing suicide. Ben stopped Locke from killing himself and convinced him he was too important to die. Locke didn't go through with his plan, but once Ben got the information he needed, Ben proceeded to strangle Locke. Ben then staged the scene so that it appeared Locke had killed himself.

Talking down a suicidal person and then proceeding to murder them moments later is one of the cruelest things a person can do. Ben once again took advantage of Locke's insecurities and made him suffer terribly as a result.

1 Letting His Daughter Die

Ben's worst crime is that he let his daughter die. Martin Keamy held Alex at gunpoint and said that he would kill her unless Ben came out of the house and surrendered. Ben was confident that Keamy was bluffing and he didn't want to appear weak in his conflict with Charles Widmore.

Ben chose pride and self-preservation over the chance to save his daughter's life. Keamy stuck to his word and pulled the trigger. Alex died as a pawn in the sick game between Ben and Widmore. This is one of the most shocking and devastating moments in the series, a moment that crossed an unspoken line and would haunt Ben for the rest of his life.

NEXT: The 5 Most Shocking Lost Deaths (& 5 We Saw Coming)

Next 10 Controversial Real Housewives Who Earned Reddit's Respect (& Why)