When you're being robbed by a street thug, you call a police officer. Who do you call if your planet is being invaded or someone is trying to steal your sun? You call the Green Lantern Corps, the policemen of the DC Universe. The galaxy has some pretty mean characters, so if you're going to lay down the law, you better bring an attitude as powerful as the Power Ring that you're wearing. But when is tough too tough?

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When you possess one of the most powerful weapons in the galaxy and you're in charge of policing an entire sector of space, what's to stop you from using a little bit of unnecessary roughness? We know that absolute power corrupts, but is it the ring that made them so cruel or was that viciousness there all along? There are many Green Lanterns known for their benevolence and their heroism, and there are others that are infamous for how they administer justice to those in the wrong. After reading this list you may ask yourself: "How did this person become a Green Lantern?" CBR takes a look at 15 of the most vicious members of the Green Lantern Corps.

15 SINESTRO

Sinestro is so devilish he went and made his own Corps to rival the Green Lanterns. But before he was slinging a fearful yellow ring, he in fact was a member of the Green Lanterns... and he did a great job!

While a member of the Green Lantern Corps, he was well respected and considered by some the greatest members of the Corps. Then there was that little matter of him setting up a dictatorship on the planet Korugar that got him banished by the Guardians to the antimatter universe. How did he become a Green Lantern in the first place? In the New 52, it was revealed that a Green Lantern named Prohl Gosgotha crash-landed near Sinestro, and instead of nursing him back to health, allowed him to die and took his ring. That should have been the first clue as to how cruel he could be. Sinestro later formed the Sinestro Corps, a rival corps that uses yellow rings that utilize fear as its power source.

14 THE CORPSE

Wait, the Corpse as in a dead body? Exactly, because that's what you'll wind up being if you're their target. Consider yourself warned.

The Corpse is the "black-ops" division of the Green Lanterns. They're so incognito that, at first glance, they don't even look like they're a part of the Green Lantern Corps. Corpse members are clad in black and don't even wear Power Rings; they ingest coin-like disks that give them the powers of the rings for a limited time. However, the constructs and energy they produce are purple, not green. Not even members of the Green Lantern Corps are aware the Corpse exist. There's a reason why they're not known: Corpse members were authorized to use lethal force prior to the rule being changed (which took place during "The Sinestro Corps War") so that all Green Lanterns could, so they are either going to kill you or wipe your memory of them.

13 KRONA

Krona is a former member of the Guardians of the Universe whose curiosity led to the creation of the very Multiverse itself! Thanks to the time and space alteration of Krona, Marvel and DC were able to have a crossover where the Justice League of America meets and fights the Avengers.

The very first attempt by the Guardians of the Universe at intergalactic police were the Manhunters, a race of emotionless robots that did the Guardians' bidding. Krona thought that having an emotionless police force was a bad idea, and came up with the equally bad idea of reprogramming them to kill everyone in Space Sector 666. The Guardians abandoned the Manhunters and created the Green Lantern Corps, so although Krona got his wish, almost everyone on the planet Ryut perished due to his tinkering. Such a lack of respect for life and a nefarious mind makes Krona one of the most vicious members of our list.

12 UNIVERSO

Universo was a member of the Green Lantern Corps. Well, not yet... technically he will be a member. Universo joined the Lanterns in the latter part of the 30th century and went by the name Vidar. As a Lantern, he stopped experiments on Earth that had the potential to reveal the secrets of the universe. It was too good of an opportunity to pass up such power and knowledge, so Vidar went rogue. Fortunately, was defeated by the Legion of Super-Heroes in issue #349 of Adventure Comics.

What makes him so vicious is the lengths he'll go to gain more power. Universo joined the Legion of Super-Villains and, during a miniseries known as the "Final Crisis: Legion of 3 Worlds," his son Rond Vidar was killed by Superboy-Prime. Not only did Universo have no problem with the death of his son, he tried to take Rond Vidar's Power Ring for himself.

11 THE ALPHA LANTERNS

"In days of peace, in nights of war, obey the laws forever more. Misconduct must be answered for. Swear us chosen... The Alpha Corps!"

There seems to be a lot of brutal people in the Green Lantern Corps, so who polices the police? The Alpha Lanterns are the "Internal Affairs" of the Corps created by the Guardians of the Universe. To be an Alpha Lantern meant more than just signing up: you had to abandon all aspects of your previous life and undergo cosmic conversion surgery, allowing them a direct connection to their power battery and never having to recharge. The Guardians believed that emotions clouded judgment, so the Alpha Lanterns were without emotion. They were draconian and they were without mercy.

John Stewart was sentenced to death for killing a fellow Lantern. Guy Gardner, along with other Lanterns, fought the Alpha Lanterns to break him free. The Alpha Lanterns were victorious due to their abilities to drain energy from Power Rings, but Varix defeated his fellow Alpha Lanterns after seeing how totalitarian they had become.

10 JOHN STEWART

John Stewart was one of many earthmen in the Green Lantern Corps. John was a veteran U.S. Marine from Detroit, Michigan who was originally considered a backup for Hal Jordan. He's also served in the Justice League from time to time. So what makes him so vicious? His killing of fellow Green Lanterns.

Fellow Green Lantern Kirrt Kallak was being tortured to extract access codes to bring down the Oan defense network. The torture was too much and Kallak was going to give up the information to stop the pain. Before he could do that, Kallak was killed by Stewart. Also, during the "War of the Green Lanterns," John Stewart was forced to kill Mogo, the Green Lantern that's literally a sentient planet, while Mogo was under the control of Krona. Although these killings were done for the greater good, the death of his fellow Lanterns was considered a serious crime and he was arrested by the Alpha Lanterns for them.

9 THE THIRD ARMY

The Guardians of the Universe get an E for effort. Their first attempt at creating a galactic police force was a race of robots known as the Manhunters. Due to a "glitch" in their programming (thanks to Krona) those robots wiped out all life in space sector 666 and also rebelled against the Guardians. The Guardians' second attempt was with the Green Lanterns, intergalactic police wearing Power Rings that had the ability to make energy constructs and fire energy beams. Although the Green Lanterns have saved the Universe countless times, the Guardians felt their emotions would get the best of them, so they decided to give it a third attempt.

The Third Army, similar to "Star Trek's" the Borg, assimilate other races and turn them into more Third Army members. They were emotionless, unstoppable, and could not be bargained or reasoned with.

8 TORQUEMADA

Besides wielding a Power Ring, Torquemade is also an accomplished magician. He learned the magic arts after the death of his family. Because of his skill set, a good deal of Torquemada's foes are magic-based. He turned one particular foe into a gold statue. He also used his magic to create ghost versions of Golden Age Atom, Doctor Midnight, and Hourman to attack Alan Scott and trick him into becoming the superhero known as the Sentinel. (Wherever happened to just asking?)

You would think that the Power Ring would be potent enough, but his usage of magic in addition to the ring makes him even more vicious in combat. You could try to take on Torquemada using magic, but it's probably not going to happen.

7 SODAM YAT

What if Superman had a Green Lantern ring? The answer can be found through Sodam Yat. Sodam is a Daxamite, and similar to Kryptonians, they get crazy-powerful when exposed to a yellow sun. Besides having the power of the Power Ring, he also has all of Superman's abilities, such as freeze breath, super-speed, superhuman strength and invulnerability to name a few.

Still not powerful enough for you? At one point, Sodam was able to draw power from the entity know as Ion. The Ion Entity gave him such additional powers as time and reality manipulation as well as immortality. With all of this power, he fought a mammoth battle with Superman-Prime and, although Yat was able to hold his own, he lost due to his physiological weakness to lead. Yat may have lost, but he put up a vicious battle that was one for the history books.

6 THE FIRST LANTERN

Volthoom was considered the very first Lantern and was empowered by the Guardians of the Universe to protect all life. Although he used the green light of willpower, he also could use additional powers from the Emotional Spectrum. Sure, the Guardians intended on him being a protector, but in the end, he sadistically tortured the very people he was supposed to protect.

The Guardians sealed him in a prison for eons in something called the Chamber of Shadows and, using his power along with the Guardians' flesh (eew) created the emotionless, unrelenting Third Army. He was able to break free and the Third Army was defeated when Volthoom took his power back. He tortured the Guardians of the Universe physically and tortured them emotionally. Although he was eventually defeated, he returned and, without anyone knowing, had possessed the body of the Guardian Rami and was plotting his revenge against the Guardians.

5 ISAMOT KOL

Kol was fighting way before he ever put on a Power Ring.  He is a Lizarkon (a big, walking lizard) and fought in the Rann-Thanagar War. During the war, he killed his commanding officer because his commander wanted to surrender to the enemy. After killing him, his troops rallied and defeated the Rannian squadron. His fellow soldiers were willing to say his death was an accident, but Kol admitted to what he did.

When fellow Green Lantern Vath Sarn lost his legs while fighting the Black Lanterns during "Blackest Knight," Kol had his own legs amputated and transplanted onto Vath. Eventually, Kol's legs grew back due to his Lizarkon physiology, but that's still an incredibly important gift. Kol's strict adherence to duty and willingness to kill fellow officers because he hates cowardice makes him a vicious Lantern as well as one you'd definitely want on your side.

4 DKRTZY RRR

Green Lanterns come in different shapes and sizes.  Some of them are as large as planets and some are as small as bacteria.  The kinds of life forms that make up the Green Lantern Corps are wild and wonderful, but Dkrtzy RRR wins the prize for being the most bizarre.

First of all, Dkrtzy RRR doesn't technically exist. It's a bio-sentient mathematical equation. With us so far? So how does this... thing work?  Can it even hold a ring? How does a mathematical equation have willpower? Dkrtzy RRR derives its willpower formulaically, adding new meaning to "I think, therefore I am." So what kind of damage can a bio-sentient mathematical equation inflict upon its enemies? Dkrtzy RRR has the power to enter and erase the brains of its enemies. Welcome to the list of vicious Lanterns, RRR. You mathematically deserve to be on this list.

3 GUY GARDNER

Guy Gardner is the Green Lantern you love to hate. In the 1980s, writer Steve Englehart and artist Joe Staton branded Gardner as an ultra-macho "red-blooded American male." Guy tends to rub people the wrong way and fights equally as hard with his enemies as he does with his friends. Although he started out on the Green Lantern Corps, he's also worn a yellow ring of fear and a red ring of rage over the years. At one point, he discovered he had Vuldarian DNA and briefly went under the codename Warrior. Instead of powers derived from his ring, he could change his body into any weapon. DC Comics eventually retconned that about him during "Green Lantern: Rebirth."

What makes Guy Gardner vicious? Not the ring on his finger, but rather the attitude of the man wielding it. He's fought most other members of the Corps when he thought he was right. He even took on Batman to prove a point (and got knocked out with just one punch).

2 JACK T. CHANCE

"You who are wicked, evil and mean... I'm the nastiest creep you've ever seen!  Come one, come all, put up a fight, I'll pound your butts with Green Lantern's light!  Yowza!"

Is Jack T. Chance a Green Lantern or a gunslinger from the old west? Besides his blue skin, he wears a trenchcoat, leather pants and a skull necklace. Even when the Power Ring forced him to wear the traditional Green Lantern uniform, he rejected it.

Pretty much every Green Lantern that was sent to the planet Garnet (also known as Hellhole) resulted in failure or death, so Pathavim Seth-Ottarak, the last Green Lantern sent there, before he died, had his ring select the only man that could police the worst criminal world in the galaxy: a fellow criminal. Besides Jack rejecting his uniform, he also rejected any formal training from the Guardians. Whereas most Lanterns police whole sectors, Jack's jurisdiction is limited only to the planet Garnet. The Power Ring may not have allowed him to kill people back then, but that didn't stop Chance from shooting people dead with his sidearm.

1 HAL JORDAN

Hal doubles as the Green Lantern Corps' greatest ally and worst villain. Hal went from United States Air Force member to Green Lantern to the man who rebooted the entire DC Universe (it's ok, it was rebooted several times after that). Hal's most vicious act occurred after a very personal tragedy. Coast City, Hal Jordan's home, was destroyed by the Cyborg Superman and Mongul. The destruction of the entire city drove him insane and, although fellow Green Lanterns were sent to get Hal under control, he wound up killing Boodikka, Jack T. Chance, Tomar-Tu, Kilowog and even Sinestro. He conspired with the villain Extant to restart the universe, but was defeated during the event known as Zero Hour.

Although it was revealed later that he was possessed by the entity known as Parallax, Hal Jordan murdered several Green Lantern Corps members as well as attempted to erase all of existence. Hal, you make it so hard to like you sometimes.

Are there any Green Lanterns that should have made our list?  Let us know who in the comments!