Percival was one of the fabled Leprechauns of Ireland visited by Ganthet and Hal Jordan. Even the ancient Leprechauns were unaware that their ancestors were once Maltusians that had left Maltus to colonize other worlds such as Earth. When Ganthet offered the Leprechauns a chance to reclaim their birthright as Guardians of the Universe, they all expressed disinterest. Much to Ganthet's dismay, only the elder Percival accepted the offer. Ganthet equipped Percival with Oan devices designed to help him better access and manage his powers while tutoring him in their proper use and a power ring until he could harness the The Glow on his own. Within a week of training, Percival grew younger and much stronger. Together the three traveled through space intent on stopping the renegade Guardian, Dawlakispokpok, and his family from using a time viewer to rewrite history. Dawlakispokpok intended on going back and killing Krona before the renegade Maltusian could unleash the anti-matter universe. What he failed to realize was that his plan would only speed up the destruction of the universe; necessitating that Ganthet and his allies stop him.
Although still a novice, Percival had tremendous willpower and fighting spirit. He engaged his enemies in combat riding atop an emerald steed clad in a constructed suit of armor. When Dawlakispokpok's son (Doranchatok) blasted through Percival's constructs, the diminutive Lantern constructed an enormous Viking warship. Again, he engaged Doranchatok in battle, and again the Guardian's son destroyed his enemy’s defenses. Using the younger man’s arrogance against him, Percival then constructed a massive battlement and rained attacks down upon his enemy like a castle of old. Doranchatok was not impressed and sped headlong into the castle intent on disbursing it as he had Percival’s other constructs. Doranchatok was unprepared for Percival’s cunning. The Lantern had positioned his battlement in front of Dawlakispokpok's time viewer and made it intangible. Doranchatok sped right through the battlement, too fast to prevent himself from crashing headlong into the time viewer. With Dawlakispokpok's machine destroyed, the anti-matter scarit’s destruction that had left the universe swallowed up the renegade Guardian.
Percival returned to Oa with Ganthet. He would later be placed in charge of caring for the New Guardians.
Sometime after the fall of the Green Lantern Corps at the hands of a Parallax-possessed Hal Jordan, Percival was captured by an interstellar slave ring dealing in powerless Green Lanterns. For some unexplained reason, the Green Lanterns did not use any of their native powers or abilities. Whether or not Percival had any powers remaining from Ganthet's instruction has not been revealed. He was among the scores of Green Lanterns freed from captivity by Guy Gardner.
Powers and Abilities
- Animating: A Green Lantern can will things to move how he wants.
- Artificial Intelligence: Every ring has a connection to the Main Battery on Oa, which taps into an artificial intelligence. It acts as an "on-board computer," telling the wearer what they need to know. It can either respond out loud, or silently directly to the wearer's mind. The AI contains a large database of information that may be crucial to a Lantern's success. The ring also translates nearly every language to and from the wearer (though they have difficulty translating profanity), which is why the Corps can communicate with each other. When the bearer of a Green Lantern ring dies, the ring will seek out a suitable replacement for their sector. The AI can be used to play a holographic playback sequence complete with colors across the spectrum based on information in memory banks. The ring can dictate when to pause or stop the playback should an interruption arise where the Lanterns undivided attention is needed. The AI can also alert the wielder of incoming threats or of attempts to manipulate the wielders construct by an outside party.
- Burglar Alarm: A Green Lantern can coat anything with the ring's beam and thus, if anyone other than himself touches it, his ring will glow, alerting him to the possible theft.
- Communicator: The ring can act as a personal communicator between Green Lanterns. They have also been seen connected to telephones.
- Costumes: The wearer of the ring may create any costume they choose, based on their personal preferences, whenever they choose. The ring projects the costume over any clothes already worn at the time. The only rules that the Guardians of the Universe implement on the creation of a individual costumed is that the ring bearer display the insignia of the Green Lantern Corps.
- Energy Projection: The rings can also project beams, form protective bubbles and force fields, and fire destructive blasts. Sometimes, depending on the wearer, the beams and blasts make sounds. Kilowog's ring is one such example of blasts making sounds.
- Energy Constructs: The rings can construct anything the wearer can imagine from hard-light energy, as long as they are willing to make it. The more determined the wearer is, the more complex and intricate these things can be. The constructs can even be so complex as to form working machines, computers, and even people. However, Hal is known for his relatively simple, straightforward constructs like his ever faithful boxing glove.
- Flight: The ring allows the wearer to fly in atmosphere or in space, and can achieve incredible speeds, moving from planet to planet in a matter of hours.
- Invisibility: The ring can make the wearer or anything else invisible.
- Matter Manipulation: A Green Lantern can use their ring to manipulate nearby matter, such as water, for various purposes such as a construct that acts like an energy construct but can block something yellow and may serve a purpose that an energy construct couldn't perform.
- Mind Control: The wearer of the Ring can use it to plant post hypnotic commands or control a person.
- Mirages: The Ring can create mirages/illusions.
- Phasing: The ring allows the user to go through walls. This ability however required great concentration on the bearer of the ring
- Power Absorbing: In the JLA's first fight with Amazo, it was GL who defeated him by drawing out all of Amazo's powers. In Green Lantern/ Silver Surfer: Unholy Alliances, Kyle defeated Parallax with SS' power and Thanos with Oa's energy by drawing out all that extra energy from them which made them unconscious. However he couldn't hold all that power nor could his Ring like Hal did with Amazo's powers, so that move isn't often used with so much power.
- Probing: The ring can probe the Lantern's or another person's mind, allowing him to uncover memories or the person's thoughts. (An ability which has not been seen for some time)
- Recharging: The rings need to be recharged by means of aPower Battery. Other large sources of power may be used to recharge a power ring, however effectiveness may vary. The internal power source of a Manhunter Android is, in effect, the same as a power battery, and can be used to recharge a power ring. During the JLA / Avengers crossover, a Cosmic Cube was used to recharge a depleted ring, although this is not an ideal solution and is available if there are no other options.
- Ring Duplication: Each ring can duplicate itself, creating a second ring which may be given to another as a backup, for protection, or to help the lantern in times of great need. This duplicate ring is exactly like a normal ring.
- Temperature Control: The Ring can increase or decrease the temperature of anything, even something as large as stars, or even create bubbles of intense heat or cold, even down to Absolute Zero. This could be seen in the recent Sinestro Corps War when Sallak used his ring to incase an enemy in a force bubble an incinerate him.
- Transforming (former): The ring can transform anyone or anything, be it into an animal, altering their state of appearance, or their size. Once Hal and Alan turned the two Flashes (Barry and Jay) to light protons in order to free them from prisons.
- Electro-magnetic scanning: The ring can allow(through the use of x rays) the user to see through walls, without the people on the other side knowing. it can also scan along the Electromagnetic spectrum.
- Wormhole/Warps: The ring can open wormholes to cut down on distance.
- Healing: A wielder can command a ring to heal him/her/itself of any injures incurred. It can also heal others. This ability however cannot regenerate lost limbs.
- Energy twin: The ring can create an energy copy of the wielder which is connected to the ring wielder, any information the twin gathers is transferred to the wielder upon touch while others cannot see this twin apart from fellow Green Lanterns.(An ability which has not been seen for some time)
- Pocket dimension: Within the ring is a pocket dimension which can altered to the wielders specification. It can be used to contain opponents.
- Sub-routines: The power rings have inner programmings or mechanisms which can executed without the users permission. One such sub-routine is the autoshield. This shield automatically protects a wielder from external harm and has been proven to be capable of protecting the wielder from planetary level attacks.