Following the end of the Sinestro Corps War and their exile from the Council of Guardians, Ganthet and Sayd discussed the changes within the Green Lantern Corps. Knowing that the Guardians of the Universe were ignoring the threat of the Blacke
The Blue Lantern Ring allows Blue Lanterns to be a conduit of hope.
Following the end of the Sinestro Corps War and their exile from the Council of Guardians, Ganthet and Sayd discussed the changes within the Green Lantern Corps. Knowing that the Guardians of the Universe were ignoring the threat of the Blackest Night, and that the Green Lanterns of Earth would be unable to stop the Black from occurring, Ganthet and Sayd decided to form their own Blue Lantern Corps, forming Blue Lantern Rings and Power Batteries fueled by hope.
Eventually, it was revealed by Relic that the Power Rings had a draining effect on the Emotional Electromagnetic Spectrum, with the Blue Lantern Rings having the biggest drain as it was the most powerful. This led him to target the Blue Lanterns first, leaving Saint Walker as the only survivor. Saint Walker's ring leaves him when he loses hope after learning what happened, but believes it was better this way, as the Blue Rings pose the biggest risk to the Emotional Electromagnetic Spectrum burning out. As such the Blue Lantern Rings presently do not have an owner.
Blue Energy Conduit: The rings use Blue energy supplied by a Power Battery, which in most cases takes the form of blue light. The Blue energy of hope has an infallible connection to the universe. Hope is the most powerful of light, and thus, the universe speaks through it. A Blue Power ring is one of the most powerful weapons in the universe and has the ability to affect and use fundamental forces of the universe, including electromagnetic energies such as gravity, radiation, heat, light, and powerful blasts of concussive force. The ring can also create fields of force formed from an unknown energy that was bound by the users' will. The limitations of such use are the skill, knowledge and imagination of the user.
- Blue Energy Blasts: The ring can be used to fire blasts of blue energy or create weapons such as projectiles of them. The ring can project beams of force powered by the will of the user. The weapon's power is more an indication of the hope of the user.
- Force-Field: The ring can create various force fields of various sizes and shapes to protect the wearer and others around him. With the cosmic scope of a Blue Lantern's abilities, it is only natural that the power ring is designed for operation in space. The ring creates a force-field around the wearer, protecting him/her/it from the hazards of the void including filtration of stellar radiation and microscopic particulate matter which would ordinarily be fatal should the space debris strike the ring wielder at high speeds. An atmosphere appropriate to the ring wielder's biology is created inside the force-field, body temperature is maintained and waste products are removed. Gravitational stresses which could cause injury are stabilized for the ring wielder. Theoretically, a ring wielder could use the ring as his/her/its sole source of life support.
- Energy Constructs: The ring can form constructs of blue energy. Unlike a Green Lantern Power Ring, the primary function of the Blue Power Ring will manifest its constructs in response to the target's specific psychosis, with a soothing effect based on that target's hopes. In this way, the ring can remove the corruptible influence of the red flame of rage by infusing hope. Otherwise, the ring is a weapon capable of transforming the wearer's thoughts into physical constructs through the wearer's mastery of hope. A Blue Lantern can create any particular item or construct that they can imagine as long as they have the mastery of hope necessary to conjure it into existence. The constructs are made out of blue energy, which is a tangible form of pure hope, and they exist only as long as a Blue Lantern is fueling it with their hopefulness. Items created by the rings are not indestructible and are only as powerful as the inspired hope of the Blue Lantern creating them. The types of constructs usually reflect the ring wearer's personality.
- Hope Empowerment: The Blue Lantern ring is unique in that its base of power, Hope, can be drawn from for strength by the ring user. Being in direct range of the emotional aura of a Blue Lantern allows them to charge an outer power reserve; by the sheer hope of the Lantern, its power will remain constant. The empowerment extends to even the stellar reactions of stars, allowing one to reverse the age of a dying star to that of a relatively newborn star. Solely empowered by the hope of the population that relied on it, in turn empowering the Blue Lantern who then collects and uses it for the purpose of transformation. The ability bypasses the need for ring energy expenditure. 
- Ring Enhancement: The primary function of any Blue Lantern Ring is the capacity to re-energize and supercharge the powers of a Green Lantern ring, for just as a green ring enables a blue ring to use its fullest functions a blue ring can augment the powers of a green one. Prolonged charging of which has the dangerous effect of overloading said ring, however, causing it to implode taking off the light wielders hand in the process. A well-kept secret among the Blue Lantern Corps is that the light of hope can empower the rings/energies of another emotional spectrum besides will, the wielder of a blue ring must willingly enable this capacity first.
- Fear Depletion: As fear is the belief of imminent demise, hope is the belief of imminent success. As such, Blue Lantern Rings are capable of depleting the energy of Qwardian Power Rings.
- Avarice Immunity: A blue ring is not vulnerable to the Orange Lantern Corps' favored tactic of draining energy from other Corps' rings. The reason of this is that while Avarice erodes Will, it can't consume Hope, thus rendering Avarice useless against Hope.
- Rage Removal: If a subject has been infected with the red light of rage, a Blue Power Ring can create a vision of the subject's greatest hope to calm and heal them. In the case of John Stewart, it showed him a vision of being reunited with his dead wife Katma Tui. The process of the removal is part spiritual and part medical: the infected goes through a cellular cleansing, with the Blue energy serving as an antitoxin to purge red plasma from the body. With a spiritual connection active, the subject's mind is alleviated and blood production is restarted. The end result is the subject being safely released from his or her ring.
- Flight: By the manipulation of anti-gravitons and directed molecular movement, the ring allows the user to fly at incredible speeds.
- Wormholes & Spacial Warps: The power ring grants its wearer access to wormholes in space, enabling the ring wielder to rapidly cut time and distance needed for transport. Black holes can be navigated by experienced ring wielders.
- Total Cellular Regeneration: Another unique ability this ring has, is the capability to heal the worst of physical injuries. Via the Light of Hope, Blue Lanterns can use the ring to repair bodily damages within themselves or others even mending severe wounds either recent or settled in such as regenerating Ganthet's lost hand or Arkillo's missing tongue.
- Electromagnetic Scanning: The ring has a wide range of detection abilities based on the imagination of the user. If one can conceive of it, they can detect it. Magical effects like clairvoyance, seem to be the most difficult for the ring. All electromagnetic phenomena are within the range of the ring, including radio, television, infrared, ultraviolet, and high-frequency band communications.
- Galactic Encyclopedia: The earlier rings worn by the Corps functioned as references for their users. Having the vast knowledge of the known universe to draw upon, each ring functioned as a ready reference on most peoples, stellar events and conditions that may have been seen by other rings or other Blue Lanterns. The rings also served as a repository of adventures had by the Blue Lantern and these mission reports were stored in the Prime Battery for review and training.
- Universal Translator: Keeping in mind the myriad of worlds, life forms, and cultures throughout the cosmos, it is understandable why Guardians of Hope added a translation system to the power ring.
- Material Alteration: The Blue Lantern's uniform is not made out of fabric. It is created by the Power Ring whenever the wearer wills to wear it. It automatically appears over the wearer's normal clothing, and vanishes when the wearer wills to return to their civilian attire. Most Blue Lantern wear similar uniforms that are programmed into the ring by default. However, each Blue Lantern is able to adjust their uniform to fit their own needs, personalities, and whims.
- Precognition: Upon receiving the ring, Blue Lanterns will experience a moment of the future by the Blue Light, directly related to the wielder and with the express purpose of lifting their hopes.
- Energy Interference: As the continuing power of the ring's connection of "universal hope", it has a tendency to cause a form of interference to other power sources.
- Willpower Symbiosis: Hope is the most powerful emotion in the emotional spectrum, but it cannot reach its full potential without the willpower to enact it. In order for the blue power ring to function, it needs the aura of green willpower, supplied by a Green Lantern Ring to be in proximity to it; otherwise, the ring will only allow limited flight, limited energy projection and constructs, and protection from the vacuum of space. Starman's sonic crystal seemed to provide a similar effect. 
- Like other power rings the Blue Lantern rings have an advanced, almost sentient A.I. which can communicate with the ring bearer. As with other rings corresponding to their colors, the blue rings emphasize hope and are programmed to spread it.
Links and References
- Green Lantern: New Guardians #23
- Green Lantern (Volume 5) #27
- Final Crisis: Rage of the Red Lanterns #1
- Green Lantern (Volume 4) #36
- Green Lantern: New Guardians #24
- Green Lantern (Volume 4) #38
- War of the Green Lanterns: Aftermath #1
- Green Lantern: New Guardians #4
- Justice League of America (Volume 2) #55