- All Reyvateils are female because the Y chromosome that males possess suppresses the Reyvateil powers, and thus precludes them from drawing power from any of the Song Servers. It's possible to override that suppression by modifying the genes to force themselves to manifest, but this in turn would create a faulty connection to the SH Server, with potentially lethal outcomes. For more details on this, please refer to the Medley and Border Disease articles.
- By singing Songs, they can draw huge amounts of power directly from the Tower (they can use Song Magic). And since the Tower itself takes care of the instrumentation and choruses for their music, their natural music talents and abilities have no bearing in how they sound when they sing Hymmnos. In other words, even the most tone-deaf Reyvateil in the world will sing marvelously as long as she does it to invoke Song Magic. 
- They can boost their magic by absorbing Grathnode Crystals into their bodies through a process called Install.
- Regardless of their aptitude for languages, they all can speak, read and understand naturally the Hymmnos language dialects supported by their respective Song Server. The only way in which this ability can be lost is if the Hymmnoserver component of the SH Server is damaged or if they are forced out of their Tower's range.
- They can directly control the tower, but only if they possess a Hymn Code or an appropriate IPD level.
- Unless they have undergone through some kind of training, they are quite lacking on the physical prowess front, needing partners to protect them.
- Almost all kinds can craft the Songs from their own feelings and experiences.
- Almost all kinds have a Cosmosphere, in which their partners Dive to help them with the crafting of their Songs (except Reyvateil Origins). 
Types of Reyvateils
The known Reyvateil kinds can fall into one of two main classifications: Purebloods and Halfbloods.
These are the Reyvateils created directly from scratch, who don't have even a single drop of human blood in their veins. Because of this, they have a higher H-Wave purity, and their songs exhibit a higher degree of power than those of the Halfbloods.
However, they also have major weakness: they are incapable of existing outside of the area of effect of the SH Server to which they are linked. This is essentially because their bodies are made from a biofluid, which is then transformed into a human-looking shape through the singing of the Nuclear Triangular Loops that exist within their bodies. If their SH-Server is destroyed, or if they go beyond its area of reach, the Nuclear Triangular Loop will cease to function, and their bodies will revert back into biofluid, effectively spelling their deaths.
Likewise, they are unable to enter the Cosmospheres of other Reyvateils, given they lack a human nature.
At birth, all of the Pureblooded Reyvateils will have the same physical and mental age as a six year-old human child, in order to make their creation and raising easier, and to avoid the problems that early childhood could cause. After this, their Cosmospheres will be slowly structured, and they will become Diveable around ten years-old, although it isn't advisable to Dive in them until they are thirteen at the very least. They will continue growing until they hit 18 years, upon which they won't age or grow anymore until their deaths.
The Pureblood Reyvateils are divided into three main kinds:
Reyvateils created from scratch. In alchemic terms, a homunculus. The Tower administers and maintains their lives, and so, as long as the Tower exists, they can live forever. However, if the Tower is destroyed, they will die as well. The Origins are mainly artificial beings, even if they also have many organic components in their bodies.
There are only 3 Origins in the world, since there are only three Towers. They are considered the parents of all the β-types and Third generations, who are directly related to one of these three origins. Each Origin's Spiritual Frequency is almost identical to the Tower they are assigned to, and they can control the Tower as if it were part of their own body. And because they are connected to an SH Server made specifically for them, unaccesable to the Dive Machines, and have their minds stored in a preset and unmodifiable ROM area, the HD-Cellophane (with one exception), they don't have Cosmospheres.
Likewise, all of them have forbidden accessing to the β-6D (Cosmospheres of the Pureblooded β-types and Third Generations) of their corresponding Towers because of security and privacy matters. In other words, they are unable to see or interfere the events happening within the Cosmospheres of their fellow Reyvateils, although parts of their subconscious can slip into the Cosmospheres of others.
Because of being capable of accessing and directly controlling the Towers, on which the people depend for their very supervivence, they are pretty much regarded as Goddesses, and boast the greatest power among the currently living Reyvateils, so much that there are some Hymmnos Extract songs that can only be used by they themselves. These are classified as Origin Exclusive Songs, and are mainly songs that control administrative functions of the Towers, such as Suspend. 
The Pureblooded β-types are Reyvateils born from nurturing DNA seeds extracted from a D-Cellophane, which in turn is extracted from a β-6D. Their life spans are rather long but extremely short compared to the virtually endless life span of the Origins (about 150 years). They will not age until they die. Origins and β-types were made while the Tower was still active, and therefore have a secured link with the Tower. Each β type is assigned an ID from the Tower so it can record all the settings in a Cosmosphere. Said ID receives the name of Hymn Code.
There are also three subclasses for the Pureblooded β-types: Neo Pureblooded β-types, β-6Ds and Generic βs.
Neo Pureblooded β-types
This is the name that was given to the Reyvateils that were being developed in an special project at the end of the Second Era. They were designed to process the songs faster and have a higher power output than the Origins had, which was planned to be done by increasing the purity of their H-Waves. In other words, stripping them from their emotions. However, the process for doing so consisted strictly speaking of setting a limiter in their Cosmospheres to reduce the amount of emotional output they could demonstrate toward emotional stimuli, allowing them to develop stronger internal emotions to pour into their Song Magic.
There was much research done, and many prototypes involved in their creation and development, but at the end, the project proved to be failure because only one of such Reyvateils came to life successfully. According to research documents that were found in recent times, there were four Neo Pureblooded β-types who were developed up to their final stage:
Of those, Mir was the only one who came to life successfully. Midir was awakened much later on by Tenba, but died upon singing EXEC_NULLASCENSION/. As for the other two, their whereabouts are completely unknown, and it might be possible that they were lost forever when the Right Wing of Horus fell. 
This is term used to refer to a Reyvateil who possesses an SH-Server for herself, but lacks a physical body. While in the past there used to be a great number of them, currently, only two β-6Ds are still in existence: the Ar tonelico β-6D and the Harvestasha β-6D. They might lack a body, but they still have their own will and feelings, and accomplish two important functions: providing the D-Cellophane used to create new Pureblooded β-Types, and hosting the Cosmospheres for the Pureblooded β-types and Third Generations. This is done by partitioning their Cosmospheres into smaller fragments, and assigning them to each individual Reyvateil. Likewise, given that these Cosmospheres actually are borrowed spaces inside β-6D's own Cosmosphere, β-6D can exert influence and partially control their actions if she wishes to do so. 
This is the name given to Pureblooded β-types that weren't created from a D-Cellophane extracted from a β-6D created by cloning the Origins, but from a cheaper, generic β-6D. Currently, there doesn't exist any of them, but they used to be very common in the First Era, given the widespread existence of many generic β-6Ds, and the fact that they were cheaper to produce than true Pureblooded β-type Reyvateils. 
Known β Types
This is an special kind of Reyvateil that was developed only in the region of Sol Cluster by the Archia Think Tank. They are all an enhanced form of the Pureblooded β-Type Reyvateils; which have as their main defining characteristic the fact that they have a far higher frequency limit for their feelings than any of the other kinds of Reyvateil, allowing their human partners to dive more deeply into them, and let them gain more power. This is translated into more conventional terms as them having a total of 24 Cosmosphere Levels. The exact purpose for their creation was the making of vessels that could absorb the Wills of the Planet, and there is only a single true living γ-Sublimate Reyvateil in the current times, due to the forbidding production costs they have, and the difficulties in making them.
The greatest difficulties in their production is that their Cosmospheres need to be hosted in an SH Server that supports broader range of frequencies than β-6D, such as the SH-Servers exclusively used by the Origins, which is a requirement for γ-Sublimate Reyvateils to fully access their unique abilities. 
These are the Reyvateils that originally were born from a Pureblood Reyvateil mother and a Human father, but in the current times, any combination of parents has the possibility of yielding a Halfblood Reyvateil daughter, as long as anyone in the family line of the girl has carried the Reyvateil gene.  Strictly speaking, Halfblood Reyvateils aren't more than humans that were misrecognized as β Reyvateils by the Song Servers due to the strength of their Reyvateil genes, which then leads to the creation of a replica of their minds inside β-6D. This process is what structures their Cosmospheres and Soulspaces, and is no more than a mirroring of all their sensations, feelings and memories inside of the SH Server, while the data contained in the Hymmno-Server flows into them, allowing them to naturally understand Hymmnos. Normally, this process takes more or less ten days, and it's always very taxing to the awakening Reyvateil, who spends most of that time in a coma, accompained by a high fever. Once this process finishes, the Install Port finally appears somewhere in her body, thus meaning that she has awakened as a Reyvateil. 
Naturally, because of being humans, their feelings are less concentrated and in some points they may be weaker than the Pureblooded Reyvateils, but they can accomplish most of their same functions, and in some cases, perform them better.
Their main advantage is that they merely use the SH-Servers to draw power for Song Magic, so even if the servers were to be shut down completely, or if they got out of their effective range, their Reyvateil nature would be put to sleep, nullifying out their powers but eliminating the need to receive Diquility doses, effectively turning them into normal humans. Of course, if anything happened to the SH Server where their Cosmospheres are located, they would still suffer grave mental damage.
The Halfblooded Reyvateils are divided into two kinds: Third Generations and IPDs
Children born from a Reyvateil mother and a human father. Most of the time, the Reyvateil capabilities are completely lost, but some of the children are born with Reyvateil powers, who are given the name of Third Generation Reyvateils. Their life span is very short, usually less than 20 years, because of the energy of the Tower surging through their bodies. Before people realized that this was because of their Reyvateil potential, it was feared as a genetic disorder called the Tattolist Disease.
Third Generations do not have a Hymn Code, but they are still connected to the Tower and are able to sing Song Magic, and can be as useful as any other Reyvateil. However, this isn't entirely true, as the Hymn Code is made by scanning and registering in the Tower's database a specific section of the Reyvateil's FFT Spectrum called the Hymn Code Zone, which is a particularly stable area located after her Lv. 9 Cosmosphere but before the Boundary Gate.
Therefore, while βs and Origins will have their spectra registered and acknowledged by the Tower, this process isn't applied to Third Generations due to how they are born, thus resulting in their Hymn Codes remaining unregistered and being recognized by the Tower as a mess of random character strings. However, about 1 in each 10 Third Generations will happen to have a random string that is exactly the same as the registered Hymn Code of a Pureblooded β-type, allowing them full connection to the Tower with all the privileges it brings. Users of the β-ER technique also have a similar process applied to them, as the usage of the D-Cellophane permanently changes their Hymn Code string to that of the Reyvateil whose Cellophane they Installed.
Known Third Generations
All the Reyvateils in Ar Ciel, except for those mentioned above.
The IPD Reyvateils are a special kind of Third Generation Reyvateils because they do not use the same Song Magic Server as the other kinds. While the other types of Reyvateils depend on either the Ar tonelico or Harvestasha servers (which share the same basic engine and thus, have compatible data structures), the IPDs depend on the Infel Phira server. They are called IPD (Infel Phira Dependency/Dependants) because of their connection to a server that is different from the Ar tonelico-based Song Servers. Also, this kind of Reyvateil does not use the standard Hymmnos dialects, but use a completely different dialect created specifically for them: the New Testament of Pastalie dialect. Additionally, given that Infel Phira does not have any authentication methods for the use of Hymmnos Extracts, these Reyvateils do not have any Hymn Codes either.
Their Cosmospheres also differ somewhat from the Standard Reyvateils by the fact that their Boundary Gates do not exist in level eight and level nine, and no IPD, with the exception of the Maiden of Mio, is able to access to these levels. Furthermore, they cannot create Mind Guardians. The deletion of their Boundary Gates, together with their final two Cosmosphere levels was made to allow the IPDs to connect to each other through their Cosmospheres allowing the usage of a higher power output to compensate for Infel Phira's relatively low power output. While they are much more powerful than standard Reyvateils, unfortunately there is a downside as they are prone to an affliction called the IPD disease.
The Reyvateil descendants of IPDs will always be IPDs, given that their Spectrum Genes are rewritten when they are born so they get assigned to Infel Phira instead of the default option, which is assigned to Ar tonelico.
An emblem-like tattoo of 5 cm of diameter  that all Reyvateils have on their body. Its location is different on each Reyvateil, but they all one, which is the point through which they can receive Grathnode Crystals and life-extending agents.
The shape of these tattoos is similar within relatives, and gives a clue to who the descendants and children are. The shape of the Port depends on the Reyvateil-type: while Origins and βs have digital, symmetrical designs in their ports, the Third Generations always have chaotic shapes. 
Reyvateils are very sensitive about anyone seeing them because this Port is a direct access to the Grathnode component of their bodies (the source of their emotions), and since anyone looking at the Port can read the emotions of the Reyvateil through it, for them it is a very embarrassing experience to allow it to be seen (similar to the entry of anyone into their Cosmosphere).
If the Installer Port ever receives damage, the LEM mechanism will make it appear in other part of the Reyvateil's body, although it also has limits to keep it from appearing in unpractical or embarrassing places: one of such examples is that the Port can't never be made to appear inside of the body or in any of its natural orifices.
Original Japanese Name: Hymmne Code (Wave Code)
It is a special identifier possesed by Origins and β types within the Song Magic Servers. The Hymn Code is a requirement for the Reyvateils to sing Extract-type hymns. This measure was put into place for the safety of the weaker Reyvateils.
However, no one among the IPDs has a Hymn Code, given that the only method for authenticating the downloads used by them is a way of measuring how much power they can handle.
A deeper explanation about how this code is set and where is located in the Reyvateil's mind can be found on the Wave Theory section.
Format of the Hymn Codes
All the Hymn Codes are formed by three parts, as we can see in the example below:
|Name of the Reyvateil||Rank||Song Server|
The first part always changes depending on the name of the Reyvateil, while the other two are subject to preestablished terms, as we can see below:
- ANSUL: Reserved only for the Administrators
- FEHU_X: Used only by the βs, and it indicates which Origin is their master copy. For example: FEHU_EORIA means that the Reyvateil is a clone of Eolia, and it translates roughly to "Subordinate to EORIA." This is also applied to the descendants of Generic βs, with the difference that their FEHU codes register their complete familiar history, ending with the generic β-6D from which their oldest ancestor was cloned.
- TEIWAZ: A new term hacked in the Tower by Mir. Has the same function as FEHU_EORIA, since it was set up as a simple redirect command.
- ARTONELICO: For the Reyvateils and their descendants that are connected to the First Tower.
- SOL=MARTA: For the Reyvateils that are connected to Ar tonelico via its relay station in the Second Tower, Sol Marta.
- HARVESTASHA: For the Reyvateils that are connected to the main server of the Third Tower, Harvestasha.
A disease that only the Halfblooded Reyvateils suffer, apparently because of their inferior resistance to the power of the Tower. This disease first manifests when a tattoo (which actually is the Installer Port) appears on the body of a girl. After that, the girl begins to suffer from a high fever, and if nothing is done, the fever and the disease will worsen to the point in which both the mind and the body of the girl will collapse, resulting in her death.
Because of this, the Halfblooded Reyvateils have an average life span of fifteen to twenty years. This disease does not have a cure, and the only treatment for it is the application of the Diquility and Tranquility crystals.
However, the Tranquility medicine does not provide a long life extension, and because of that, it is only used to relieve the tiredness that Reyvateils suffer in battle from singing, while the Diquility is the crystal actually used to prolong their life spans. The Diquility is often referred to as the "Life-Extending Agent," and it needs to be given to Halfblooded Reyvateils every three months to prolong their lives. The installation of a Tranquility crystal is generally painless, but on the other hand, the installation of a Diquility ends up being excruciatingly painful.
And unfortunately, the Diquility crystals cannot be broken or grounded up before being installed because that would release the Static H-Waves contained within them, causing them to lose their life-extending properties.
However, no matter how many doses of Diquility are given to them during their lifetimes, Halfblood Reyvateils won't live past 40 years, since the LEM won't be able to continue maintaining them alive due to the minimal amount of physical and mental strength it needs to function.
A more in-depth explanation of what causes this disease and how both Life-Extending Agents work can be found on the Wave Theory section.
This sickness can affect any Reyvateil hosted in an Ar tonelico-based server, and it is very similar to the IPD disease described below. This sickness does not have any known cure, and it is caused by a virus that was spread in the Ar tonelico server in recent times. It is only described and shown in the Ar tonelico ~Arpeggio~ side story manga. Reveris means "nightmare" in Hymmnos.
This is a disease than only affects the IPD Reyvateils, and originated from the destruction of a part of Infel Phira during the war, and the accumulation of negative feelings inside of Infel Phira.
The disease it's said to manifest itself in two forms: Positive and Negative. The positive form is an attack of madness where the Reyvateil loses conscious control of herself and begins attacking anything in her range of sight, potentially ending in her own death. The negative form manifests as a sudden outburst of fever and loss of consciousness. Whenever the negative form manifests, the disease can be spread to any Reyvateils that are approximately fifty meters around of the infected one. However, the negative form is merely the symptoms of a girl awakening her Reyvateil abilities, but it was linked to the IPD outbreaks because of the awakening causing a severe overload of frustration, fear, and anxiety, which would end triggering an outbreak if the girl was to awaken as an IPD Reyvateil.
- ↑ Technical Service Center, Toukousphere #45
- ↑ Ar tonelico Official Visual Book: Reyvateil Section
- ↑ 3.0 3.1 3.2 Ar tonelico Official Settings Material Collection: Encyclopedia Section
- ↑ Hymmno Server: Hymmnos Kinds Section
- ↑ Technical Service Center, Toukousphere #60
- ↑ Technical Service Center, Toukousphere #99
- ↑ Ar tonelico Hymmnos Musical Claire: Promise of the Breeze
- ↑ Ar tonelico III Official Settings Material Collection. Wave Theory Section
- ↑ Toukousphere: Issues 74, 75, 108.
- ↑ Ar tonelico III Official Materials Collection. World Section: Keywords
- ↑ Ar tonelico Official Visual Book: Reyvateil Section
- ↑ Technical Service Center, Toukousphere Issues #75, #80, #83 & #84.
- ↑ Ar tonelico II Official Setting Materials Collection: History Section.
- ↑ Ar tonelico II Official Settings Material Collection: World Section
- ↑ Technical Data Compilation Room: Issue 3
- ↑ Toukousphere: Issue 36
- ↑ Ar tonelico Official Setting Materials Collection: Wave Theory Section.
- ↑ Ar tonelico Official Settings Material Collection: Wave Theory Section.
- ↑ Ar tonelico Official Site - Ar Portal: Toukousphere Issue #61
- ↑ Ar tonelico - Arpeggio - Manga: Chapter 1
- ↑ Ar tonelico II Official Settings Material Collection: World Section
- ↑ Ar tonelico II - Tutorial: Terminology section