Power ring

Power rings are the weapons and tools wielded by the Green Lantern Corps and other users of the Emotional Spectrum.

Origin
The first appearance of a power ring was in All-American Comics #16 (July 1940), the flagship title of comic book publisher All-American Publications, which featured the first appearance of Alan Scott. Green Lantern's original alter ego was Alan Ladd, a play on the name Aladdin, until a conflict arose regarding the actor Alan Ladd. Creator Marty Nodell has cited Richard Wagner's opera cycle The Ring of the Nibelungen and the sight of a trainman's green railway lantern as inspirations for the combination of a magical ring and lantern. It has been claimed that another original inspiration for the Silver Age interpretation of Green Lantern was the Lensman series, a serial science fiction space opera, by E.E. "Doc" Smith, but the creators have vehemently denied this claim.

Alan Scott's ring is powered by the Green Flame (revised by later writers to be a mystical power called the Starheart), a magically empowered flame contained within an orb (The orb was actually a green, metal meteorite that fell to Earth which Alan Scott found. This was later explained as just a fragment that cracked off of the main Starheart that was still floating in space) which was fashioned into a lantern and ring by the character. Unlike the objects featured more prevalently in modern comics, "[s]cience in the original Green Lantern series was never a concern." This early version of the ring is shown as being powerless against wooden objects.

When the Green Lantern character was reinvented, beginning with the introduction of Hal Jordan, the magical ring concept was replaced with a scientifically based one. The new version of the ring is created by the Guardians of the Universe, who also create the Green Lantern Corps. They divide the universe into 3600 sectors, each patrolled by two Green Lanterns equipped with power rings to assist them in their duties. The new concept for the ring also came with new limitations (though they would be removed or altered in later volumes). Specifically, the ring's charge would only last as long as one planetary rotation of the ringbearer's home planet, which for the Green Lanterns of Earth is twenty-four hours and "due to a flaw in the unique metal that powers the battery" was ineffective against anything yellow. The power ring is fueled by the willpower of its wearer.

Capabilities
No hard upper limit to the power ring's capabilities has yet been demonstrated; it is often referred to as "the most powerful weapon in the universe."

The power ring's most distinctive effect is the generation of green, solid-light constructs, the precise physical nature of which has never been specified. The size, complexity, and strength of these constructs is limited only by the ring-bearer's willpower; whatever the wearer imagines, the ring will create.

When active, a power ring will encase its user in a protective, life-supporting force field. This force field allows the user to fly, travel through inhospitable environments (outer space, underwater, etc.), and enter hyperspace in order to move vast distances quickly. The ring also generates its wearer's Green Lantern uniform: the uniform appears over their normal attire and vanishes at the user's will. The uniform varies from Lantern to Lantern, based on anatomy, personal preference, and the social norms of their race. The only rule in this regard seems to be that the uniform must openly display the symbol of the corps, though even this has been modified based on preference, (a vampire-hunting Lantern adapts the symbol into a cross, and a blind Lantern with no concept of light or color uses the image of a bell) as in the case of Kyle Rayner who wears a modified version of the symbol on his uniform.

Power rings also appear to be highly advanced computers; they are able to talk to and advise the wearer as to various courses of action, as well as act as a universal translator. The ring can also scan for energy signatures or particular objects. For more intricate problems or problems that require a back logged history (Of a planet, person, group, ETC.), the ring connects with the main power battery on Oa which is the "main" computer, of sorts.

Power rings are able to give off electromagnetic radiation of various frequencies. This radiation can be focused by the wearer into a beam, similar in appearance and effect to a powerful laser. The ring is also capable of producing an electrical current. Less frequently used capabilities include splitting atomic nuclei and manipulating subatomic particles (thereby transmuting chemical elements). A power ring is also capable of creating fully functional duplicates of itself.

While power rings have to be worn to be effective, at several points Green Lanterns have shown the ability to summon the ring to them from a distance (even if someone else is wearing it) or order it to carry out commands automatically after being removed. Some power rings have been shown to be genetically keyed to the wearer, like Kyle Rayner's, though villains have circumvented this through various means. For instance, Manhunters use tissue samples to make Kyle's ring think it is still on his hand. When a Green Lantern is slain, their ring will automatically seek out a suitable replacement after logging the death for record. While the Green Lantern ring is an extremely advanced computer and is highly intelligent, it cannot think for itself. The ring will only act if it is given instructions by its wearer. Also, when a wearer expires, it will seek out a new replacement, but at that point, Mogo, the planet sized Green lantern takes over telepathic "custody" of the ring and issues its commands helping it find a suitable new recruit. Without Mogo, the ring would just transport itself to Oa and fall to the ground inert until it is needed again.

Limitations
Originally Green Lantern power rings typically held a limited charge. In earlier appearances, they required recharging every twenty-four hours, but more recently they possess a fixed amount of regular charge: that is, the charge is good for twenty-four hours of 'typical' use, but extended or extensive use will drain the charge more quickly. Green Lantern rings typically reserve a small portion of their power for a passive force field that protects its wielder from mortal harm. In dire emergencies, that energy reserve can be tapped at the expense of said protection. Power rings are usually recharged by a Green Lantern's personal battery, which looks like an old fashioned lantern made of dark green metal. The user typically points the ring towards the lantern, and usually gives the Green Lantern oath (below) while recharging the ring. These batteries are directly linked to the Central Power Battery on Oa and do not themselves need recharging.

Originally, power rings were unable to affect objects colored yellow, though Lanterns have typically found ways around the limitation by indirect manipulation. The reason why the rings were unable to affect yellow objects has changed significantly from writer to writer. In early stories, it was because of a design flaw. Gerard Jones revised this, in a story that revealed that the Guardians could change the weakness randomly and at will. After the destruction of the central battery Ganthet revealed to Kyle Rayner that an "imperfection" in the central battery was responsible for the yellow weakness (which his ring didn't have as there was no Central Battery). In Green Lantern: Rebirth, writer Geoff Johns revealed that the "yellow impurity" was the result of Parallax, a yellow energy being made of pure fear, which had been imprisoned in the Central Power Battery. This change to the fictional history also allowed characters to overcome the yellow weakness by recognizing the fear behind it and facing that fear.

By far, the most significant limitation of the power ring is the willpower of the wielder. The requirements needed to wield a power ring have changed sporadically during the history of Green Lantern titles, often creating continuity confusions. Allowing power rings to fall into the wrong hands has been a favorite plot device in many previous Green Lantern stories. However, only people with exceptional willpower can use a power ring, a restriction which makes use of the rings by average individuals incredibly difficult (if not impossible). For instance, when Green Arrow used a power ring to attack Sinestro, it pushed the hero's body to the point of exhaustion (and for all his effort he was only able to generate a single arrow, which did little to Sinestro other than annoy him). Mind control, hallucinogens, psychic attacks, "neural chaff" and other phenomena that disrupt thought processes will all indirectly impair a power ring's effectiveness. More abstractly, so can a weakening of resolve and will. For example, during the Millennium crossover, Hal Jordan fights a Manhunter who psychologically attacks him, to make him doubt that the people he is protecting value the principles he is fighting for. Jordan's resolve begins to weaken and his ring loses effectiveness until one of his charges strikes the Manhunter, declaring that she does deeply value Jordan's principles as well. With this dramatic affirmation, Jordan's faith in his cause is restored and the ring instantly returns to full power. The ring, though, does have some psychic defenses: Guy Gardner's ring apparently is able to put up psi-shields around him and Blue Beetle in their battle against the Ultra-Humanite. There is also a limit to the amount of willpower the ring can take, as seen when John Stewart attempted to use his ring to re-build a destroyed planet, only to have his ring inform him, "Willpower exceeding power ring capabilities."

In the current incarnation of the Corps, the ring originally possessed programming to prevent the wearer from killing sentient beings. Hal Jordan was thought to have used power rings to kill a number of Corps members during Emerald Twilight, though he did tell Kilowog that he "left them enough power to survive." During the Sinestro Corps War event, they were revealed to be alive, held prisoner by the Cyborg Superman on the planet Biot. These Lanterns are referred to as the "Lost Lanterns". Any attempt to kill using a green power ring was automatically diverted, and in some cases resulted in the ring locking out the user. However, this restriction was rescinded by the Guardians to combat the Sinestro Corps, then for the general execution of their duties.

It has been claimed in-universe that only a pure form of willpower can use the ring effectively. When Green Arrow tried to use Hal Jordan's power ring against Sinestro, it caused him great pain and difficulty because (according to Sinestro) Green Arrow's will was "cynical". It has also been shown that the user's stamina is drained with every construct. When Green Arrow fires a small arrow-like construct from the ring, he describes the experience as feeling like losing a week's worth of sleep. When he questions Kyle Rayner about this, Kyle affirms that the feeling is normal.

Oaths
All power rings need periodic recharging. When doing so, many Green Lanterns recite an oath while the ring charges. The oath is not required to charge the ring, but is recited to reaffirm the person's commitment to the Green Lantern Corps. While many Green Lanterns create their own oath, the majority use the Corps' official oath as a sign of respect. This practice has been abandoned with the reinstating of the Green Lantern Corps. As additional Corps have been introduced into DC continuity, with their own power rings (see below), corresponding oaths unique to each Corps have been formulated as well.

Kyle Rayner's ring
After the destruction of Coast City during the "Reign of the Supermen!" story-arc, Green Lantern Hal Jordan goes mad and betrays the Corps. He defeats most of the Corps on his way to Oa, enters the Central Power Battery, and absorbs most of its energies along with the yellow impurity to become the villain Parallax. With the Central Power Battery destroyed, all the remaining power rings stop working. In desperation Ganthet, the only surviving Guardian, uses what little power remains to create a new power ring and gives it to Kyle Rayner.

Kyle's ring is unique throughout the history of the Green Lantern characters, and was for a time the only working power ring throughout the DC Universe. His ring is not dependent on the Central Power Battery, and is free from the yellow impurity. However, the ring does not prevent mortal damage automatically. The ring no longer needs to be charged every twenty-four hours; instead, its use is based on how much power it absorbs when recharging and how much is expended when it is in use. For example, after the destruction of Oa, Kyle's ring has more power than ever before and does not need to be recharged for an extended period of time. Unlike Hal Jordan's ring, it is unable to make copies of itself. After Kyle became settled into his role as the new Green Lantern, a Hal Jordan from the past visits Kyle's time after his own death as Parallax. He gives a copy of his ring to Kyle, which has the ability to replicate itself. Kyle attempts to use Hal's ring to restart the Green Lantern Corps with limited results.

The apparently random induction in the Corps, more than once contested by Ganthet as simple fatality during most of the Green Lantern v3 run, is later retconned into the very first induction of a new breed of Lanterns. Since the Corps become aware of the Emotional spectrum, and the crippling effects the yellow light of Fear radiated by Parallax has over the green light of Will radiated by Ion, the Lantern Rookies are not anymore chosen by merely People unable to feel fear, but from people able to feel, and overcome, their fears. Since Kyle had always been able to do so, wrestling against his fears for his entire life, his ring gained immunity against the Yellow Impurity and his particularly fortified will was instrumental in bringing upon the rebirth of the Corps and setting an example to follow for the newer recruits.

Before giving up the power of the Central Battery Kyle further modified his ring. He gave the ring a permanent back up charge (so his ring could never be totally powerless). He also designed a recall feature that if his ring were ever removed from his hand that it could be summoned by him where ever he was.

Other Lantern Corps
In the hidden section of the Book of Oa, there was a prophecy about the War of Light and the Blackest Night. It foretold of the rise of several other Lantern Corps after fear rises (The events of the Sinestro Corp War). Tapping into the emotional spectrum, each corp is connected to a particular color as well as a corresponding emotion from which they derive their abilities.

The corps that exists are as follows: red (rage), orange (avarice), yellow (fear), green (willpower), blue (hope), indigo (compassion), violet (love), black (death), and white (life).

According to Ganthet, the farther from the center of the spectrum the color is, the more control the ring's power has over its user. Therefore, green rings are the most stable, while red and violet rings exert the most influence over the behavior of their users. Artist Ethan Van Sciver, who worked with Geoff Johns on the concept of a spectrum of power rings, described their development:

We found the idea of the seven different colors and what they meant, and then we tried to see what each of the different corps would represent and what kind of people they were.

I always call it a religion. I think of these different colors as religions. And I use that word with Geoff, and I'm not sure that he agrees. But the way I think of it is that they all sort of focus around one sort of human drive. Not even an emotion. I know it's called the emotional spectrum, but I tend to use the word "drive," because willpower isn't as much an emotion as a human drive. You have the willpower to get something done.

Van Sciver designed aspects of the other Corps. According to Johns: "Ethan redefined the way Green Lanterns' energy is used visually. He started the "siren" symbol and now it's everywhere. He also designed the various Corps' symbols and there's a rhyme and reason to them all."

In Green Lantern and Green Lantern Corps comics, these additional Corps are introduced as part of a forbidden chapter on cosmic revelations in the Book of Oa. Included in this chapter are the prophecies about the Blackest Night. At the end of the Sinestro Corps War, former Guardians Ganthet and Sayd reveal to the four Earth-based Green Lanterns the final verse of the prophecy. They explain to the Lanterns (and the reader) that the prophecy describes the formation of five more Corps in addition to the Green Lantern and Sinestro Corps; one for each of the remaining colors of the emotional spectrum. They go on to say that after these additional forces have come together, war will break out between the seven Corps until they destroy each other and the universe. These seven Corps described within the Blackest Night prophecy are joined by a final Corps not described in the text. Slowly revealed through the machinations of the Guardian Scar and the mysterious appearance of a black power battery within various issues (beginning with the Anti-Monitor's absorption into it at the conclusion of the Sinestro Corps War), a Black Lantern Corps is also formed.

Red
Atrocitus, a member of the Empire of Tears on the prison planet Ysmault, forges the first Red Power Battery from the innards of Qull, the being who tells Abin Sur the prophecy of "the Blackest Night". Red power rings are powered by rage, feed on the rage of their users and anyone nearby, and are charged by the blood of those the user kills. Unlike Green Lantern rings, which provide a helpful commentary to their user, red rings are depicted as constantly emitting violent commands ("Kill," "Rage," "Pain," "Hatred," etc.), driving their wearers insane with rage and reducing them to little more than snarling beasts. The rings, however, seek out beings with great rage.

A user's red ring functionally replaces the user's heart, tainting their blood with red energy, and forces it out of their body through their mouth as a highly corrosive substance. The red ring's energy is also capable of corrupting the energies of other power rings, keeping them from functioning properly. The aura of a red ring is savage and rough in comparison to a green ring, but can be used similarly with sufficient focus, as Atrocitus demonstrates by creating a giant construct of Mera. Originally, a Blue Lanterns' energy was the only known power source capable of neutralizing the Red Lanterns' influences, and are also the only means of removing a red power ring from its user without killing them. Mogo managed to purify Guy Gardner during the Blackest Night but as Guy has not been cured by a Blue Lantern, traces of the Red Rage remain. Also a Star Sapphire, working with a Red Lantern's true love, is capable of restoring a Red Lantern.

Orange
An orange ring is powered by avarice. Unlike the other Corps, Larfleeze (initially known as "Agent Orange") is the only living individual to wield the power of the orange light, although Lex Luthor briefly shared that power during the "Blackest Night" storyline.

Some of Larfleeze's abilities are shared with other Corps: flight, aura projection, and orange light constructs. As a side effect of wielding the orange light, Larfleeze is burdened with an insatiable hunger that is never quelled regardless of how much food he eats. The power of the orange light allows Larfleeze to steal the identities of those he kills, transforming them into an "Orange Lantern" construct. These Orange Lanterns are able to steal the identities of others for Larfleeze in the same way. The orange light also has the power to absorb the energies of other power rings. However, it cannot absorb constructs produced by violet or blue power rings. By being in constant contact with his main power battery, Larfleeze has become one with his power source. This allows him to maintain a power level high enough to support an entire Corps of orange light constructs even when separated from it. Larfleeze and his constructs are resistant to magic and the abilities of green power rings, but do not retain the same protection against blue or violet rings. The blue light of hope can also nullify his insatiable hunger when he is near a bearer of it.

Yellow
The first yellow ring is acquired by Thaal Sinestro following his banishment to the antimatter universe of Qward, and could only be recharged by fighting a Green Lantern. After his imprisonment in the power battery his ring was taken by Guy Gardner who used it until it was destroyed by Parallax. Upon his return to life, Sinestro was seen wearing a new yellow power ring. Before he could be defeated Sinestro retreated to the anti-matter universe where he spent the year creating his Sinestro Corps.

Yellow Power rings are now fueled by fear instead of willpower, but function the same as their green counterparts. Members of the Sinestro Corps are chosen for their ability to instill great fear in others. In order to become a member of the Sinestro Corps, one must free themselves from a small prison. With their yellow power ring completely drained of its energy, they must provide it with the spark it needs to accomplish this feat by facing their own greatest fear. Originally Yellow rings could be charged by Manhunter androids that have yellow power batteries built into themselves, which in turn are connected to the Central Yellow Power Battery on Qward. There are also portable batteries similar to those used by Green Lanterns. Aside from the recharging limitations common among the various Corps, their only known weakness is that their power can be drained by a Blue power ring or disrupted by a Red Power Ring.

According to Ethan Van Sciver, the ring's symbol is based on ancient carvings made by beings who had looked into the gullet of Parallax and survived.

Blue
As the Sinestro Corps War ends, former Guardians of the Universe Ganthet and Sayd create the first blue power ring. The home planet of the Blue Lanterns and the Central Blue Power Battery is the planet Odym, an idyllic planet orbiting the star Polaris. Blue power rings are fueled by hope; they give their users the most power, but they must be near an active Green power ring to tap into their full potential. Otherwise, the blue rings are only capable of default abilities (flight and a protective aura). This is because hope requires willpower to enact it. Blue rings must be fueled by true hope in order to operate at their user's command.

While within the proximity of a Green Lantern's ring, a blue ring can heal wounds, neutralize the corrupting effects of a red power ring, block the energy-stealing properties of orange rings, can drain the power from yellow power rings, and recharge a green power ring to twice its maximum power level. This effect can also negatively impact a green ring, as close proximity to the blue central power battery will overcharge a green ring, causing it to implode (taking the user's hand with it). If a Blue Lantern wishes it, it can also dampen the hunger caused by the orange light. A noteworthy ability of blue rings is the power to scan a target's psyche and create illusions based on their hopes. A blue power ring is capable of feeding off the hope of other beings, eschewing constant recharging while still performing impressive feats, including reversing a dying sun's age. Blue rings can also grant precognitive visions to their wielders.

Indigo
The Indigo Tribe, wielders of the indigo light of compassion, make their first extended appearance in Blackest Night: Tales of the Corps #1 (July 2009). Unlike other Corps, the Indigo Tribe carry carved, lantern-like staves with them. In Blackest Night #5, it is established that Indigo Tribe members use their staffs instead of power batteries to charge their rings. In addition to being able to store indigo light energy, they are also capable of replicating the power of other emotional lights as well, providing indigo power rings access to the abilities of other Corps. To use the power of another Corps, Indigo Tribesmen must be in the vicinity of one of that Corps' members. Without that closeness, their access to the abilities of that emotional light fades.

Like all power rings, indigo rings are capable of the default Corps abilities of flight and protective aura generation. Indigo power rings give their users the ability to perceive compassion in others and to force compassion onto those who feel none. Paradoxically, indigo light has the ability to heal individuals with great empathy and to expose people to pain they've inflicted on other people. Indigo Power Rings can teleport their users and others over intergalactic distances. This ability utilizes a great deal of power from an indigo power ring, and Indigo Tribe members try to use it sparingly.

Violet
At the conclusion of the Mystery of the Star Sapphire story-arc, the Zamarons realize that the power of the Star Sapphire gem is too great for them to control and forge a Violet Power Battery and power ring out of the Star Sapphire gem, using the bodies that sparked the Star Sapphire as a mediator. This allows them to distribute its powers throughout an entire Corps of Star Sapphires.

Violet power rings are fueled by the emotion of love. They allow their wearer to fly, generate a protective aura (which creates distinct feathered and organic shapes), and create violet light constructs. Violet rings have several unique abilities. They can create crystals which can be used to imprison members of other Lantern Corps on the Zamaron planet. Over time, the rings of the prisoners trapped in stasis within the crystals are infused with violet energy. After spending enough time inside, the prisoner will emerge as a Star Sapphire. The rings can also detect when a love is in jeopardy, locate it, and then create a connection to the embattled heart that can be used as a tether. Sapphires are also shown as being able to show others their greatest love. Unlike constructs created by Green Lanterns, Orange Lanterns cannot absorb those made by Star Sapphires. Star Sapphires are able to teleport in order to escape attackers, while their constructs release a disorienting dust when destroyed. These two abilities can be combined effectively to avoid being pursued. Violet power rings can restore the recently deceased to life by drawing power from the heart of one that loves them.

Although Violet Power Rings do not have a particular weakness to other colors, they are more susceptible to controlling their user by their own power. Love is one of the two emotions on the far ends of the emotional spectrum, and has a much stronger influence over its user. Unlike the Star Sapphire gem, which could force itself on a user, violet power rings must be accepted by the wearer."

Black
Black Power Rings are fueled by death, instead of a light from the emotional spectrum. In the concluding issues of the Sinestro Corps War, Superboy-Prime hurls the Anti-Monitor into space. His dying essence crashes onto the dead planet of Ryut and is encased in the Black Central Power Battery. Black Hand becomes the first Black Lantern after killing his family and committing suicide; Scar comes to him and regurgitates the first black power ring. As noted by Ray Palmer, the structure of black rings is similar to dark matter. The symbol on black power rings (a triangle pointing down, with five lines radiating up) is the same symbol used by Green Lantern villain Black Hand and his family.

Black power rings are wielded by the deceased. In addition to the abilities granted to them by the rings, Black Lanterns retain any superpowers they may have had in life. If the ring bearer's body is severely damaged or destroyed they can bring the body back to life, the black ring will partially reconstruct the body, restoring it to a working state. Black Lanterns rings are able to read the emotions of the living as colored auras that correlate to the emotional spectrum. Multiple emotions read as a multi-colored aura, while unreadable emotions come out as white or black. A state of suspended animation is also enough to fool a black ring's senses. Emotionless hearts, such as Scarecrow's, render their bearers equally invisible to Black Lanterns. When facing beings with warped mental states or otherwise addled minds, the correlation between the emotion detected and the color seen is inverted.

A combination of green light with any other light of the emotional spectrum can neutralize black rings, rendering them vulnerable. Once a black ring is destroyed, the corpse it animates becomes inert. Black Lanterns are vulnerable to white light, described in Blackest Night #3 as the "white light of creation." Other methods exist for destroying Black Rings. Kimiyo Hoshi and Halo can destroy black power rings using their light-based powers. Conner Kent uses the Medusa Mask to force two Black Lanterns to experience the fullness of the Emotional Spectrum, irritating their black rings enough that they remove themselves and flee. Superboy-Prime takes control of a black power ring and is forced to experience all of the emotional spectrum except for hope, forcing the ring to shift abilities and uniforms as his emotions go out of control. The ring ultimately detonates. The "touch" of a Black Lantern, used to remove their victims' hearts and drain them of emotional energy, can sever the connection between other Black Lanterns and their black ring. Time travel can deactivate a searching black ring.

Some characters have been shown as able to resist black rings for various reasons, including: having once been a zombie, being immortal, or being a Red Lantern. Wonder Woman and Conner Kent were also able to fight their ring's control.

White
The first white power ring is depicted during the Blackest Night event. It is worn by Sinestro after he bonds himself to a creature embodying life itself, known as "the Entity." The exact capabilities and limitations of white power rings are still unknown, but they have been shown as capable of providing their bearers with the default Corps abilities of flight, protective aura generation, and light construct creation. Their most notable and unique ability to date is the power to restore the dead to life. The first instances of this ability were shown not by the intention of any individual, but by the ring itself. They are also shown "overriding" power rings of other colors, turning them white for a period of time.

Boston Brand, aka Deadman, was brought back to true life through the power of the white ring. Unable to control it or remove it, the ring rendered him invisible and teleported him across Earth and Mars so that he could observe events "The Entity" deemed important. His white ring allowed him to make constructs of other lanterns, similar to the orange light, but only when he was in danger and expressed a desire to keep living.

The white ring has recently shown a darker side. Having been charged up by Boston's embracing of his new life, the ring then commandeered him, forcing him to take it to see various resurrected individuals. When Hawkman and Hawkgirl refused to follow its orders, it acted independently to kill them, much to Boston's horror. It then teleported him to Aquaman's location and killed him as well, despite Boston's desperate attempts to gain control of it long enough for Arthur to get away.

Amazo's Power Ring
Justice League of America villain Amazo employs a power ring duplicated from the ring of Green Lantern Hal Jordan that appears to have all of the capabilities and weaknesses of the original, save the need to recharge every 24 hours.

Anti-Green Lantern Power Ring
An early predecessor to the Black Lantern Corps is the Anti-Green Lantern Corps, where the Weaponers of Qward tapped into the Black Light and produced their own black power ring-empowered force that rivaled the Green Lantern Corps. Unfortunately, the will power necessary to use the rings required its bearers' to have augmented brains that when the rings lose their charge after 24 hours, the bearer loses their life.

Black Hand's Power Rod
While built by Atrocitus, a rod-like energy device was primarily employed by the Black Hand before he was modified by Evil Star. This device would consume Green Lantern's energy and allow Black Hand to employ the abilities of a power ring dependent on the amount of energy it stored. This device was also shown to absorb the Speed Force and redistribute it to another object.

Black Light's Power Ring
In the Batman Beyond comic, a villain is introduced named Black Light with a black power ring but it was discovered this ring merely manipulated energy from the Green Lantern's ring.

Corpse Disks
In Green Lantern Corps, an additional division of the Green Lanterns is introduced: "the Corpse". This elite, top secret, black ops division of the Green Lantern Corps does not incorporate the use of standard power rings into their work. Instead, they swallow a small disk that gives them all the powers of a standard ring for the equivalent of five Earth days. Rather than generating a typical Green Lantern uniform, Corpse disks create a completely black uniform with a mask that totally covers the user's head. Their energy aura is also purple instead of green. The disks are meant to encourage discretion, as a Green Lantern ring is a distinct and recognizable weapon. Not only are Corpse abilities less conspicuous, but (in the event of a failed mission) no connections will be made between them and the Guardians of Oa.

Enforcer's Power Gauntlet
The clone of Guy Gardner that would take on Guy's middle name of Joe and the alter ego Enforcer was visited by the demon Neron whom offered him power in exchange for his soul. The result was a yellow power gauntlet that seemed to be capable of all the abilities of Sinestro's yellow power ring.

Krona's Power Gauntlet
Krona's Power Gauntlet served as the prototype of the Green Lantern power rings. It is a metallic glove attached to a large disc on the users back. While the Gauntlet seems primitive to the power rings with the inability to make complex constructs, it can make very powerful energy beams and radial blasts.

Manhunter Pistols
Before the development of the power rings, two groups are depicted as preceding the Green Lantern Corps within DC continuity. The first, the Manhunters, are armed with energy pistols that are specially attuned to the hand-held battery from which it draws power. The battery itself holds a connection to the Central Power Battery on Oa; operating as its own source of energy. This mode of energy transference is not unlike the kind used by power rings. After the Guardians lost control of the Manhunters, the Hallas, a race of green-skinned aliens from Sector 2814, are shown as pre-Corps Oan enforcers in Green Lantern (vol. 2) #90 (August 1976). Like the Manhunters, they are also shown wielding stun guns attached to Lantern batteries.

Starheart
The first superhero to use the name Green Lantern in comic books, Alan Scott, uses a power ring that draws energy from the Starheart. Before the creation of the Corps, the Guardians gathered all the magic they could find and imprisoned it in an orb called the Starheart. In its original appearance, a flashback sequence depicts how a fragment of the Starheart falls to Earth, is discovered by a Chinese occultist, and fashioned into the shape of a lamp. Superstitious villagers murder the occultist, after which, the lamp flashes green, killing them in return. After traveling the world for some time, the lamp eventually ends up at an insane asylum. It is here where a patient reshapes it into a train lantern, whereupon the power of the lantern restores his sanity. It comes into Scott's possession during a train wreck where it grants him the power to wield it. To channel its power, he removes a portion of it and molds it into a ring. The only weakness of the ring is that it cannot be used to affect things made of wood. Residual effects from wearing it were, however, passed down to Scott's children, the metahumans Jade and Obsidian.

Jade was able to tap into the Starheart naturally and use its power without the necessity of a ring. For a time, Alan Scott absorbed the Starheart, and was able to use the power in a similar fashion. When Jade died, Kyle Rayner absorbed her energy, and could tap into both the Starheart and the Central Power Battery as Ion. During the Sinestro Corps War story-arc, Rayner was separated from the Ion entity (a benevolent symbiote and living embodiment of willpower) and became a normal Green Lantern again after being given a standard Green power ring. It is unclear if Rayner's link to the Starheart remains, or if it was transferred with the Ion symbiote to its newest host, Sodam Yat.

During the Brightest Day event, it appears that the Starheart actually has its own sentient intelligence that controls its user, as it is revealed that the orb had been gradually taking control of people on Earth for quite some time, and now that it is on Earth, it is growing more powerful and driving metahumans all over the world insane. Jade states that the Starheart captured her in space and deliberately brought her to Earth to find Alan, and also states that it is her fault that her father is now in danger. Just then, Alan awakens and his costume transforms into his suit of armor from Kingdom Come, and he then tells the assembled heroes that he intends to destroy the world.

Sucker Stick
Designed and employed by Doctor Ub'x, the Sucker Stick was a staff that employed science and sorcery to be a device that rivaled the Green Lantern's power ring. Able to manipulate energy and fueled by willpower, it appears able to replicate the power ring's abilities without its weaknesses.

Tangent Green Lantern
On Earth-9, the Green Lantern uses a magical verdant Chinese lantern that when placed atop a grave will resurrect the dead, giving them a "Second Chance" to complete what they left unfinished in life before returning to the afterlife. The artifact also offers communication with the dead and across dimensions, teleportation (including between universes), can mask the bearer's presence, and can detect energy in the vicinity.

Volthoom's Power Ring
Given to who would become the first in a line of supervillains named Power Ring by the mad Buddhist monk and mystic Volthoom, this green power ring appears to have all of the powers and abilities of a Green Lantern ring (along with a power battery lantern), though can effect wood and yellow. However, Power Ring murdered Volthoom after obtaining the ring and the monk's spirit seems to inhabit the item, haunting whomever bears the ring. As the Crime Syndicate of America are villainous counterparts to the Justice League of America, the identity of Power Ring seems directly connected to which Green Lantern is in the Justice League at the time. Further, with the introduction of Earth-3 and its Crime Society of America (a quasi-union of supervillains with analogies to the Justice League and Justice Society of America similar to Alexander Luthor, Jr.'s Society), there is at least another Volthoom power ring if not several. Volthoom's Power Ring is magical in nature in a similar fashion to the Starheart.

Yellow Lantern's Ring
The Yellow Lantern is a Bizarro character with an especially strange power ring. Once the charge of his Yellow power ring ran out, it was rendered effectively useless as he was unable to recharge it with any of the Green power batteries he encountered. The New Earth version of Yellow Lantern, introduced in Action Comics, did not have the same problem recharging his own power ring. He was, however, depicted as incompetent, unaware of the extent of his abilities, and incapable of maintaining control over his disobedient power ring.