Warning Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled.
This article is about the real life information about Project Alicization and its mechanics. For information about events within Underworld, please see Underworld.

Project Alicization (プロジェクト・アリシゼーション, Purojekuto Arishizēshon?) is a top-secret government project run by Rath to create the first Highly Adaptive «Bottom-up AI». The Japan Self-Defense Force (JSDF) wish to use the AI for unmanned weapons to improve Japan’s weak defence technology, and to take the place of soldiers in wars in order to reduce human casualties. The name Alicization is formed from the acronym A.L.I.C.E (Artificial Labile Intelligent Cybernated Existence;[1][2] i.e., a Highly Adaptive Artificial Intelligence), as the aim of the project is to turn the Artificial Fluctlights into «Alice», which the staff refers to as «Alice-ing». The name might also be a reference to “Alice in Wonderland”. The project is mainly being conducted within Rath's main base, the «Ocean Turtle», though a secondary facility in Roppongi is also used.


With the era of the Cold War, and later, the collapse of the Soviet Union, people became less and less tolerant of the death of soldiers, while countries with large militaries, especially America, have been unable to give up their army munitions industry. With such conditions, the need for unmanned weapons to replace soldiers had arisen. However, as no countries export weapons to Japan, Japan's defense technology became too weak and, eventually, Japan had to buy new equipment from America. Although formally America is supposed to work together with Japan on developing new technology, in reality Japan has only been given outdated equipment. Thus, the need for Japan to develop its own technology came.[1]

History and developmentEdit

Early ExperimentationEdit

To create a truly adaptive «bottom-up» type AI, it is necessary to replicate the structure of the human consciousness, in other words, a quantum field, called a «Fluctlight». For this purpose, a 4th generation FullDive machine, called the «Soul Translator» (STL) - which could read and copy a human’s «Fluctlight» - and a special quantum computer - capable of storing the hundreds of millions qubits worth of the Fluctlight’s data - was created. With the use of the STL, it was possible to successfully capture a Fluctlight. Attempts at cloning an aged human’s Fluctlight turned out to be futile, as the clones could not handle the fact that they were not the originals and mentally collapsed after an average of three minutes.[1]

After a week of brainstorming, an alternative plan to limit the memories of the cloned Fluctlights was created, as a Fluctlight without memories of its personal information, like name or address, is not likely to go into a hysteria of not being the original that would lead to its collapse, but this plan also proved to be a failure, as Artificial Fluctlights are not as easy to manipulate, due to learning also being a form of memory, meaning that the loss of the memory of successfully using an ability leads to the loss of the ability.[1]

Later ExperimentsEdit

Finally, it was decided to clone the Fluctlights of newborns, which had no memories yet and this plan was successfully implemented by scanning the Fluctlights of twelve newborns (their parents, of course, were not told what the scans were truly needed for). As, according to Higa Takeru, Fluctlights, especially those of newborns, do not have any physical differences in them like genes, meaning that a newborn Fluctlight clone does not have a specific personality, it was possible to create a «Soul Archetype», which could then be inserted into the virtual world where it could grow and develop into a new individual.[1]

Creation Of UnderworldEdit

The world required for nurturing the Artificial Fluctlights would need to be extremely vast, nearly equal to the level of modern society, but even the STL is not capable of completely reproducing the virtual world. That is why it was decided to bring the level of the civilization in the virtual world to a past era, when science and philosophy were just being discovered, so that it would be easier to nurture the AIs under certain conditions and prevent them from realizing that their world is a fake. Unfortunately, the people behind this project were complete amateurs to the cultural and social norms of the past era, so, instead of recreating a past era, it was thought that limited terrain and customs would be enough to create different settings for the world which could then be adjusted when needed, with all troublesome issues being resolved by the term "magic".[1]

Although creating a virtual world within the STL mainframe would not require any 3D data, creating the model data would be too uninteresting to do, therefore, the free kernel version of the Cardinal System, «The Seed», was downloaded and used to create the villages and landscape of the new virtual world and then transferred into the STL mainframe using the visual mnemonics feature of the STL, with the Cardinal being left in charge of balancing the created VR world. That is how the world of «Underworld» came to be.[1]

Population and Development of UnderworldEdit

The first sixteen AIs were created and nurtured in two farming families with NPCs filling in the role of other villagers. However, the first AIs could not be nurtured by another AI, so four Rath employees volunteered to enter Underworld and raise the first AIs to the age of eighteen (with the FLA rate set to 1000, meaning that only one week had passed in real life), after which, they were logged out by simulating their death via an “epidemic” and their memories of their time in Underworld being suppressed. As the human volunteers logged out, the FLA rate was increased to 5000 and the sixteen AIs, four boys and four girls in each of the two families formed their own families with ten children. As the children were raised and eventually formed families of their own, the number of Artificial Fluctlights in Underworld quickly multiplied and gradually replaced the NPC villagers. In three weeks of reality or 300 years of simulation, the population of Underworld reached 80,000 and the Artificial Fluctlights expanded from a small village to occupying most of Underworld and even created a central government structure and their own religion. A feudal system started to develop in Underworld, with royal families and the Axiom Church ruling over the world. Although there is no logical need for this kind of system in Underworld, it most likely came about because one of the original four Rath workers sent in to create a society had different intentions than the others. It is most likely that they had less ethics than the other three and wanted their children to rule the world. These thoughts and feelings were then passed on to their children and thus the feudal system started to take shape.

Underworld Experiment ProblemsEdit

However, even though the AIs were growing with the same level of intellect as humans, a problem was discovered. Namely, in the 300+ years of simulation there had not been a single war, not even a single killing, due to the Artificial Fluctlights being overly obedient and not being capable of breaking any laws or rules set upon them.

Early TestingEdit

The first attempted experiment to test the obedience of the residents of Underworld was called the «Overload Experiment». This involved causing the crops and livestock in the farms of an isolated village to die off to such an extent that the villagers would not have enough food to last through the winter, unless they abandoned a certain group of villagers so that at least the others could survive, therefore disobeying the Taboo Index by killing someone. However, the experiment turned out be a complete failure, as the villagers distributed their meager harvest among all villagers and none of them survived the winter due to starvation. This experiment proved that the residents of Underworld are not capable of breaking the law even for their own survival.[1]

Due to the results of the previous experiment, it was necessary to find out why the residents of Underworld were not capable of disobeying the law. Thus, another experiment was proposed. Eight volunteers from Rath were chosen to have their memories blocked and they were to grow up in Underworld from birth to the age of ten again in all sorts of environments to see if their actions would be similar to those of the Artificial Fluctlights. The result was that not only did none of the eight test subjects break the Taboo Index before the age of ten, but they also turned out to be less lively and curious of their surroundings than the regular residents due to a sense of discomfort. This was because their memories could not be erased completely, making them unable to get used to the life in Underworld, since the world does still differ from the real world.[1]

Later TestingEdit

Finally, it was decided that a new test subject, who is used to living in a VR world and would not feel discomforted while living in Underworld was required. Kirigaya Kazuto was selected for this role due to his experience with living in virtual worlds for extended amounts of time, namely the game «Sword Art Online». He was also chosen because of the level of proficiency he displayed and capability to adapt within the game. Unlike the testers from Rath, Kirito exhibited an unseen level of curiosity and activity, being on the verge of breaking the Taboo Index many times, although he never actually broke any of the laws. However, Kirito's influence did make Eugeo and Alice Zuberg, the people closest to him, more likely to break the Taboo Index, until one day, Alice finally broke one of the clauses of the Taboo Index by touching the soil of the Dark Territory in an attempt to save the life of a dying Fluctlight. However, due to the time in Underworld passing at a much higher rate than in the real world, by the time the staff at Rath managed to notice that somebody had broken the Index, two days had passed in Underworld and Alice had already been transported to the Central Cathedral of the Axiom Church, where she was forcefully synthesised.[1]

Load Test StageEdit

The «Final Tolerance Experiment» (負荷実験段階, Fuka Jikken Dankai?, alternatively, "Final Load Test") is the final phase of the project, during which, the residents of the Human Empire were intended to face off against the creatures of the Dark Territory. A gradually increasing «load parameter» gradually increases the amount of endemic diseases, rampancy of dangerous beasts, poor harvest of crops, eventually causing an invasion of the Human Empire by the Dark Territory. This parameter cannot be changed even by a being with maximum System Control Authority, thus the Dark Territory's invasion on the Human Empire is inevitable. This phase is meant to test what kind of resistance the residents of the Human Empire would exhibit as their world slowly crumbles.[3]

System mechanicsEdit


Unlike the usual VR games, there is no game menu in Alicization. Instead, a Status Window called a «Stacia Window» can be called out for any object and person by drawing a seal shaped like the alphabet letters S and C with one's hand and tapping the target that one wishes to inspect. However, as the «Stacia Window» is considered as a basic form of «Sacred Arts», calling out the window for larger objects is considerably more difficult than for smaller objects and requires sufficient practice and knowledge in the Sacred Arts. The Status Window shows the ID and current/maximum «Life» values of the targeted object, as well as the item's Priority class if the item is a weapon, or Object Control and System Control Authorities if the target is a sentient being.

As a menu does not exist, an item storage feature does not exist either, meaning that all items need to be carried by hand, while clothes and weapons can be equipped the same way as in real life, instead of via a menu. Logging out manually is also impossible due to this, and it is presumed that only an Administrator can log a player out from within the game, though Kirito speculates that dying in-game might also lead to logging out.


The stats for any object or living being can be viewed by calling out a «Stacia Window» for them. Everything in Underworld has a property called «Life» while humans also have stats called «Object Control» and «System Control» Authorities and certain items, like tools and weapons have a property called «Priority». The OC and SC authorities were implemented for the project's «Pressure Experiment Stage», during which, the residents of Underworld were meant to battle with creatures from the Dark Territory to strengthen themselves.

Unit IDEdit

The Unit ID is a parameter that most every object and living creature has. This ID is typically alphanumeric, and is seemingly ordered by the sequence in which that object was created in a specific category. The Unit ID usually begins with a string of characters that identify the category they belong to. For example, «WLSS», which is presumed to stand for «Double-edged, Long Sword, Single-hand»,[4] usually precedes any unit that has the aforementioned characteristics.

Additionally, Human Units also have a Unit ID that can be seen when bringing up a Stacia Window. This Unit ID is preceded by a string of characters, which likely identifies the location in Underworld that the Unit was born in.[5] Integrity Knights also have a secondary ID, which identifies them as "Integrator Unit"s and consists of three numerical digits. This secondary ID is not proceeded by a string of characters, so it is presumed that this ID is somehow different from the usual Unit IDs.

These IDs, for both Objects and Living Units, can be utilized with Sacred Arts for various purposes, such as locating a Unit, or modifying one of a Unit's many parameters.


«Life» (天命, Tenmei?, "Durability" in a status window) is the name given to the durability or HP value of each object or living being in Underworld. Unlike in RPGs, a user's Life is not displayed in their interface and can instead be checked by calling out a Stacia Window. The maximum amount of Life each individual has increases with age, peaking for humans at around twenty years old, but starts decreasing after the peak of one's lifespan is reached. Each object and living being has a different amount of Life available, which seems to depend on the lifespan of their real life equivalents, for example, insects and flowers have far less Life than trees and rocks. Life measures the current state of each object and depends on the conditions the object is kept in.

Most objects in Underworld do not disappear immediately after running out of Life. Most of them start a new count of Life as shards, fragments or carcasses, though the Life of such broken objects decreases at a far greater rate and disappears completely, without a trace, once the Life reaches 0 again.

For food, Life gradually decreases with time, but the rate of Life decreasing greatly increases in hot weather and, once the Life of food runs out, it becomes rotten, causing various illnesses if such food is eaten.[6] For clothes, Life controls various defects and stains and will drop rapidly if the clothes are not washed.[7]

For humans, Life drops at a rapid rate if injuries and illnesses are not treated in a timely manner. Bleeding is especially dangerous to a person's Life, as it causes a constant decrease in Life, making Life recovery rituals useless until it is sealed. Bleeding can be stopped by either sealing the wound, for example with cloth or any similar material, or by using special Sacred Arts. Fatigue in the world is treated as an illness, thus a person's Life drops with extensive running, holding on to large weight or anything else that leads to fatigue. A user becomes weaker as their Life decreases, even resulting at the user becoming unconscious when their Life reaches a critical level. Although there is no other way to control one's maximum Life aside from Administrator-level rituals, the currently available Life can be restored via medication and Sacred Art rituals (the most effective being the risky Life transfer rituals), though they cannot increase it beyond the maximum limit.

When a human's Life reaches 0, white arrows of light rain down on the said person, causing the insides of their head to be shaved away bit by bit, in other words, the system begins deleting the person's Fluctlight. A dead human can still be revived, unless important parts of the Fluctlights are shaved off before the ritual takes place. A resurrection can never be done perfectly, as the bits of Fluctlight that are shaved off until the ritual is cast cannot be restored. In a best case scenario, the revived person will only have lost their memories of the past few days.[8]

Object Control AuthorityEdit

«Object Control Authority», abbreviated as OC Authority, is a parameter that determines what kind of tools, weapons and armor the person can wield. A person needs to have an OC authority equal to or higher than the item's «Priority» class to be able to wield the item properly. Swords that have a higher Priority than a person's OC authority cannot be used to perform «Secret moves», i.e. Sword Skills and they will feel much heavier than they should to the user. A sword's Priority determines the maximum hit combo Sword Skills that can be used with it and higher Priority items are also capable of breaking lower Priority items. The OC authority parameter can be increased by killing any creature that is capable of moving, even other people, but a larger increase in the parameter is awarded for killing creatures from the Dark Territory.

System Control AuthorityEdit

«System Control Authority», abbreviated as SC Authority, is a parameter that determines what «Sacred Arts» rituals one can use and their success rate. Like OC authority, SC authority can be increased by killing any creature capable of moving, creatures from the Dark Territory providing a bigger increase, or through steady use of the rituals, even if they are not performed successfully, but with a bigger increase with successful difficult ritual usage.

Hidden parametersEdit

Aside from the visible parameters like Life, OC and SC authority, several hidden parameters for each being exist as well. One of such parameters is called «Transgression Quotient» (or «Taboo Breaking Index») that measures the person's compliance to the law and rules through their speech and conduct which is converted in numerals. This parameter was originally meant to be used by Rath employees to monitor how likely an Artificial Fluctlight is to break the Taboo Index, but, after this parameter was discovered by Quinella, she used it to find humans who were skeptical of the Taboo Index and posed a threat to her rule.[3]


Sacred ArtsEdit

Main article: Sacred Arts

«Sacred Arts» (神聖術, Shinsei-jutsu?) are System Commands in Alicization that residents of Underworld believe to be magic rituals. In reality, they are just words used to arrange thoughts and guide the emotions of the caster to make use of one's imagination power. Because of this, the imagination of the user may either improve or decrease the effectiveness of an art.[9]

Secret MovesEdit

A list of all known Sword styles and their Secret Moves can be found at: Sword Skills

«Secret Art Finishing Moves», usually shortened to just «secret moves», is the name that Underworld residents have given to Sword Skills existing in Underworld. It is currently unknown how these skills were implemented in Alicization, as ALO, which uses a complete copy of the SAO servers, is the only game that has the data for Sword Skills, since «The Seed» package does not include them.

Secret moves work quite similarly to the Sword Skills in SAO. A Secret Move is activated by assuming a certain stance with one's weapon, called an opening motion, which triggers the activation of a certain pre-programmed move which cannot be stopped midway. However, one major difference between Secret Moves and Sword Skills is that the highest possible consecutive hit combo of a Secret Move, unlike Sword Skills in SAO, is limited by the wielded sword's priority. The priority of wooden swords that are used for practice in the Master Sword Academy and tournaments seems to be enough for only 2-hit moves, while «Divine Instrument» class weapons with a priority of 45-46 allow up to 4-hit moves to be used. However, the residents of Human Empire only use 1-hit skills, because they do not believe that more than one is possible, until Kirito employs multi-hit skills.

Fluctlight ReplicationEdit

When a male-female couple, who have registered a marriage in the system by pledging their marriage to the god Stacia in a ceremony conducted by the village chief (or, after churches were established, monk or nuns in the churches), have sexual intercourse, there will be a certain probability for a new Fluctlight model to be loaded into an empty cube within the Light Cube Cluster, with a part of the parents’ external elements and their patterns of thoughts and character inserted, forming a newborn baby after a period of pregnancy.[10]

Incarnation SkillEdit

Incarnation (心意, Shin'i?) refers to a principle within Underworld which allows an individual or group to alter the state of the world through imagination and will. It is a secret skill passed down to Integrity Knights since ancient times. Only several Integrity Knights are able to use this skill.[11]


For storing the Artificial Fluclights and mnemonic visual data of Underworld, a powerful quantum computer, «Quantum Particle Gate Crystallization», also known as «LightCube» was created. The 5cm construct of the LightCube is made from Praseodymium crystals, which can store hundreds of millions of qubits of data, in other words, it is capable of storing the data of a cloned Fluctlight.[1] The mainframe of the STL is made from a cluster of hundreds of thousands of systematically arranged Light Cubes, each storing a single Fluctlight and connected to a center massive cube that stores the extensive «Mnemonic Visual» data of the Underworld residents.[12] The Cluster, with each side measuring three meters, is covered by a metal shell, which makes the cluster look like a simple rectangular box.[12]

The LightCube, located in the middle shaft of the Ocean Turtle, is connected to two STL machines on the upper shaft and two more on the lower shaft, while the original STL prototype in Roppongi is connected to the LightCube via satellite.[13]


Spoiler Alert! [show]
*In the end of the web version, after Rath's satellite network was disconnected, it was still possible to connect to Underworld via the IP address after deciphering a message sent to Alice anonymously.


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