So, some people told me to make a Guilty Gear blog because Guilty Gear is confusing and whatnot. So I made this for you, anyone out there reading this, confused of Guilty Gear lore and abilities and need help. Sorry for full Japanese scans you will see, I'm playing JP version. Let's start.
Gears
Gears are living weapons created in 21st century. The Gear project was started to evolve all lifeforms to something further beyond using a artificial cells known as gear cells. The project's head was none other than Asuka R. Kruez, also known as Gearmaker.
Anyone who became Gear will lose their sense of self, becoming more similar to machine. When Justice, the only Gear that has its own consciousness went berserk, ordered Gears and manipulated them at her will. There are Gears that managed to escape Justice's control and gained consciousness and knowledge even better than humans.
After the Crusade, with Justice's defeat, most gears went into deep sleep. The creation of gears and gear cells were illegalized ever since. Some Gears went into a continent of Australia to have a peaceful live, most notable being Paradigm.
Gears, and even half-Gears’ aging process is extremely fast. Dizzy, who looks like in her late 20s, is actually 8, while Sin, who looks like in his late teens, is actually 3. This, doesn't mean that they are mentally young. Gears have superb ability to collect and absorb information, meaning they have the same age of what they look mentally.
One of the first priorities Asuka had of creating Gears is to be able to withstand Backyard, an universe with high density information. They also are able to use virtually infinite energy if used correctly.
They have regenerative capabilities, as even by human with few Gear cells was able to heal fatal gunshots, including the chest, because of the fact that Gear cells multiplies the speed of multiplication of cells by merging them. Some Gears are even able to regenerate from puddle of blood or to regenerate from ash, as in case with Testament and Sol. This cells also stops any diseases that will plague mankind, as it is also one of its primary motives before it turned into creating weapons. These functions make Gears live longer than humans.
Gear cells can be restricted by a device, named Gear Cell Restriction Device. With this, a full Gear can maintain a human form, as it stops the effects of Gear cells to the body. The only person who uses this is Sol with his headgear.
Time Slipper
Time Slippers are beings that are able to directly intervene with space-time continuum, creating disturbance in physical phenomenons, and even manipulate matter to create objects. They are also able to disturb causality and even erase timelines.
Time Slippers mainly use their abilities to time travel called time slip. They are able to do this by riding on a special flow of time that connects past, present and future together. They are even able to travel to different timelines using this ability. The process of this is a bit close to Einstein's theories on time travel, though it was only able to travel to future. The true mechanics of this ability is unknown, even by That Man or Sol. In fact, Sol stated that existence of Time Slipper is hard to take.
Time Slippers’ origin comes from the Crusade, during humanity had strong will to have a tomorrow, creating a lifeform. Backyard recognizes the as an error, sealing it inside human's mind and gives it a lot of irregularities. Time Slippers are already separated from their past and future.
Backyard
Backyard is a dimension with extremely high information density. The connection of the universe and Backyard is similar to programming code and software. Universe is a software while Backyard being the instructions for the software. It means that Backyard is the “program” in itself and doesn't exist physically. For more example, if the universe is a sentence, Backyard is the words. Sentence can only be made and made sense of by collective words within it. Sol stated that Backyard is a virtual space, though Izuna, who is likely much more of an expert in this regard, stated that the universe is the virtual space, not the Backyard. Just like the earth can't exist without the universe, the world can't exist without the Backyard.
Backyard was theorized to give an origin to Magic's five element configuration. In other words, it is a place where information that defines fundamental truths of the world. Backyard is a place that determines the law of the universe. Magic is nothing more than borrowing said information to manipulate something from the world. Sol also agreed that Backyard is bigger than the universe.
While Backyard doesn't exist per say, getting to Backyard is theoretically simple. Any teleporters who will teleport to Backyard will swap the space of universe and Backyard, then returning it to normal, effectively getting into dimension.
Anyone who will enter the Backyard without any protection or being Gear will be their consciousness, body and soul because of the sheer difference of tuning between universe and Backyard. This doesn't affect what is basically an object, however.
The Dream World is part of the Backyard, the place where the consciousness go when anyone is dreaming.
Also note that the Backyard is a higher-dimension.
Information Flare
Information Flare is an event that can be caused by Adam and Eve, also known as Sol Badguy and Justice/Jack-O Valentine. This is also shown to be used by Universal Will upon entering the universe with Justice from the Backyard. This is just a mere side effect of Absolute World.
Universe's space has a particle called information particles inside them. It is a document and program in a space that dictate what are the matter that should be in the said space and in what condition. The information particles stored inside the space is already dictated naturally, that being 256PB per cubic meter. But when Coraeptal annexation occurs and Belhend imaginary coefficient cannot maintain consistent values against space and time alongside the H-axis, will break the limit of the information particles that can be stored within the space, breaking space to enter the physical universe.
Since the flare of information will make the space unstable, even small amount will shake the entire area and in large amount, will create weird phenomenons within the area, though this usually won't affect humans. This is especially true in the Backyard, since the information there is virtually infinite.
One of the most dangerous effects of Information Flare is Possession, which is, in spite of its name, isn't a spiritual phenomenon. Possession is a phenomenon when the information of matter is rewritten to turn into another object entirely. It can also cause genetic mutations. At worst, the information of the matter completely flips, turning matter into antimatter. This is done when information Flare gets worse.
Absolute World
Absolute World is an event that instantly makes all lifeforms across the entire universe. This will be taken place just by Adam and Eve, or Sol and Justice/Jack-O, exist simultaneously, merging the universe and the Backyard for just a moment, erasing everything inside that can't take it.
The only ones who are capable of surviving Absolute World are Adam and Eve and thus, they are arguably immortal.
Absolute World also seems to disperse matter like a cosmic ray. This happens in our real life, when a deadly rays outside our earth collides with our atmosphere, they will get decayed to smaller rays. Absolute World will likely able to do this as well, as Jack-O is able to detect Secondary Cosmic Rays to be able to detect Absolute World.
Saint Oratorio
Saint Orotario is the power source of Outrage and the type of energy that Sol studied before turned into a Gear. It is basically a type of limitless energy.
Outrage
Outrage is the weapon created to combat the Gears during Crusade by Sol. It has the power of Saint Oratorio, meaning it has limitless energy. It is mainly used to amplify user’s magic. Because of its dangerous potential, the weapon was split into eight parts called Sacred Treasures.
Fireseal and Zenga was used by Sol and fused to create Junkyard. Thunderseal is currently at the hands of Ky while Zessen is at the hands of Anji. The other two Sacred Treasures are in possession of PWAB while other twos’ whereabouts are unknown.
Junkyard
Junkyard is made out of two Sacred Treasures: Fireseal and Zenga.
Fireseal is a sword that doesn't have edge, taken by Sol in secret during Crusade. It is a weapon that converts the user’s power to firepower. Fireseal can't be used by normal person, needing someone with enough power to take the firepower of Fireseal and should have strong mind to do so. Sol was able to use this weapon like his hands and feet.
Zenga, while it's form is mostly unknown, is able to manipulate light magic. It was taken by Sol during Vastedge.
At some time after Vastedge, Sol fused the two weapons, creating Junkyard Dog.
Thunderseal
A sword used by Ky during Crusade. It is a sword that can manipulate lightning magic. It also can be used as a sealing device, as what he did to Dizzy during Overture, when Ky sealed her in a space that has slowed down time, to the point of near halt, with her body seemingly turned into stone.
Zessen
A fan used by Anji throughout the series. It is used to manipulate wind magic. It also can manipulate chi, sound and electromagnetic signals, teleport and create dimensional barriers. It is also used by Anji to track other people from far away, as seen in Accent Core.
Magic
Magic is a so-called "super natural" energy that obliterated the oil market during 21 century. It's unit is called Ziel and it counts similar to joules and volts. It is currently used by everyone's everyday life, from lighting up fire, creating lightning and so on. It is, of course, also used as combat mechanics. It is discovered by the Original Man upon entering the Backyard.
Magic has five element configuration: fire, electricity, water, wind and ki. Though there is light magic. These configurations are "already within your body" and there is no better or lower affinity to it, and thus with very unstable emotions, even in childhood, the user can manifest it or lose it completely, in fact these cases are going on around the world. The most mysterious of them all is ki, because scientist can't really explain this element. Ki can only be used by Asians or at very least, people who were taught by Asians, especially Japanese.
The people who are outside of five element configuration are the one who are born in the Backyard, such as Valentine and Izuna with few exceptions like That Man and Paradigm. The normal magic are completely nulled and useless against them and their magic couldn't be nulled by normal magic. Not just that, their magic is harder to learn than normal magic.
Teleportation Magic
Teleportation Magic is a magic that is considered to be a pinnacle of magic, needing extreme mathematical skills and magical knowledge to pull it off. At certain point, it will defy the fundamentals of Magic itself, such as Izuna's teleportation.
The reason why the teleportation magic users aren't thrown out of the gravity because of the sudden change of altitude and latitude is because they tweak with their inertia. Another example of skill of teleportation users.
Valentine
Valentines are the copies of Aria/Justice created by either Universal Will or That Man. They are created from the Backyard, with purpose of merging with Justice to create Absolute World, with exception of Valentine, whose objective is to merge with the Cube.
Crusade
A catastrophic event started when Justice went berserk. Long story short, it was 100 year war that took place from 2074 to 2175, with the war destroying the likes of Tower of Liberty, most of Australia and Eurasia. It was a war that made humans almost extinct. The war ended by sealing Justice in an alternate dimension, led by Ky Kiske, followed various knights, including Sol.
Baptisma 13
An event that drove Gears to near extinction and almost destroyed Illyria led by Valentine in 2186. The gears are suddenly erased from existence all across the world, including the likes of Dizzy, by Valentine. This is because Valentine is destroying any kind of footholds that will enter the Backyard and merge with the Cube, a device That Man has created to warp reality on universal scale. With combined efforts of Ky, Sol, Sin, Paradigm and Izuna, the former managed to defeat Valentine's army while the latter four managed to defeat Valentine in the Backyard. Valentine, extremely angry, trapped Sol in the Backyard and tried to die with him, but she ultimately failed, ending the event with That Man rescuing Sol from Backyard, sending him back to the world.
Magical Weapon
Magical Weapon is a weapon that is half-alive. It is created when an information within the Backyard possessed a viable physical body, then becoming stable as a result. Many Japanese Gods and Youkais are created by this phenomenon. The most notable of them being Paracelsus and I-No.
Underworld Hill
Underworld Hill is a place closer to Backyard than the real world, being inhabited by Youkais like Izuna. It has no physical point in space, and transcend time itself. Mysteriously, there is no doubt that someone must be created it artificially, not by natural means. It is totally possible to even say that it is created for humanity itself, though the real origin is unknown.
Youkais
Youkais are arguably the natural predecessors of Gears, they can even be controlled by Valentine. They are created in the Backyard similar to Valentine and I-No. They live in Underworld Hill, a dimension close to the Backyard. The most notable of them being Izuna.
Tuning
Tuning is an ability to manipulate the flow of ki behind all things, manipulating physical phenomenons in the process. Just like how a good tuning in music gives you good sound, good tuning to reality gives you stable state of matter and phenomenons. It is also used to increase strength and health. The perfect tuning is currently said to be impossible and shouldn't be aimed. The only Tuner is Kum Haehyun.
Vampires
Vampires are creatures with lot of unknown things, though there are basic knowledge of them: they are immortal, they suck up blood (or vitality), they obey orders from their master, they are far above any humans and they are weak to sunlight, cross, garlic, etc. The only vampire currently known is Slayer.
Cube
Cube is an extremely powerful tool that is created by That Man for unknown reason and the reason why Baptisma 13 was occurred. Cube is a quarantined space that is made that it is closed to outside world, which is hard to believe even by Sol. The ability of the Cube is to manipulate the Backyard's information, effectively able to manipulate everything around it. It can mess with reality and fate, make impossible possible, change fundamental laws and truths and so on. It was ultimately destroyed by Sol at the end of Overture.
Second Knight of the Holy Order Selection Tournament
A tournament held by Conclave and Testament, long story short, it was a tournament to choose who will defeat Justice, but in actuality, Testament held the tournament to get Justice out of the dimensional prison. Testament succeeded at the cost of his own life and Justice killed Kliff by overexhaustion. Sol killed Justice at the end as Conclave wanted him to do which will eventually be explained during Cradle Incident.
At the very start of the Crusade
It was year 2074 and Justice were controllable and had will of Aria. She was entering the Backyard when suddenly, she was attacked by Universal Will, controlling her mind. Trying to enter the Backyard, Universal Will started to create information flux and flares and turning Justice's information comparable to galaxy cluster. Universal Will's energy is so strong that it overpowered an entire lifeforms worth of energy easily. It multiplied within her DNA exponentially, multiplying its body to two, then three, and so on. By the time it will appear in the world in few seconds, it multiplied to 388. Within an hour, the Earth will no longer be human world. With no option left, Asuka manipulated Justice manually then fired the gamma ray at Japan, vaporizing it completely. Then on, Justice went berserk, starting the Crusade.
What's worse is that Universal Will was able to reincarnate as human, becoming Ariels, torturing other Apostles with madness and diseases.
Dawn of Revival
At the year 1999, all electrical circuitry was possessed by Universal Will. Radio, television, internet, all of them were hacked. After that, all electronic devices were suddenly either stopped working or created weird phenomenons. The world, which was reliant on technology at the time, were thrown into absolute chaos. Even worse, the world was then suffered an earthquake and several cities were disappeared at the same time. It was so bad that UN decided to ban all electronic devices and do a major rehaul on society as a whole. The world was then saved by Apostles, the students of the Original Man, spreading knowledge of Magic all over the world. With new power that connects the world, the crisis was then averted. In 2008, they became Sanctus Populi.
Cradle Incident
Cradle Incident happened when a giant Cradle appeared at Babylon, swallowing it and sending it to the Backyard, killing every lifeform within it completely. Ramlethal then nuked the country then threatened to do it to humanity as a whole, then she waited in Japan. She then was captured by Sol with help from Elphelt. It was just the start of the incident though, and Conclave were busted with help from Zato-1, who was the guinea pig for resurrection experiment, and Paradigm who were warned by That Man. UN attacked the Conclave and the Cradle but unfortunately, they were unable to destroy it, and Conclave were managed to transform Cradle to Justice. Conclave were then tried to awaken Justice and fuse Chronus' soul to her using Saint Elmo's energy. The heroes foresaw this however and Paradigm and Dizzy fired an energy at Chronus, making him absorbing too much energy, then Sol stopping the fusing of soul between him and Justice.
Absolute Defense: Felion
A barrier that provides extremely powerful protection from physical and magical attacks. It is near impossible to break, even by Sol and nullifying it is also hard, as even That Man can't do it. It was only nullified once when Sol and That Man created a miniature black hole.