Diclonius

Diclonius (pl. diclonii) is the name given to a fictional subspecies of humanity from the Japanese manga and anime series Elfen Lied. The original manga once referred to them with the word "elf."

They are characterised by two rounded horns emanating out of the skull (which resemble cat ears), and the telekinetic ability to manipulate solid matter, which is manifested through the use of limited range invisible or translucent non-corporeal arms extending out of their backs, known as "vectors". A diclonius' vectors can be several meters in length, and are many times stronger than the physical human body, allowing a diclonius to telekinetically lift objects many times their own weight and hurl them with tremendous force, or to dismember an enemy by pulling them limb from limb or simply punch them. They can also be used to telekinetically shield a diclonius from projectile weapons, rendering most guns useless against them (with the exception of heavy-caliber armor-piercing ammunition). Vectors can pass through living flesh without causing harm, but if a diclonius wills it their vectors can become unbelievably sharp (by causing it to vibrate at a microscopic level), capable of effortlessly slicing through just about anything - including human flesh and bone. Diclonii also possess a limited psychic ability, in that they can sense a fellow diclonius' presence via telepathy over short distances. Diclonius mutants are theorized to be an emergent new race, in direct evolutionary conflict with normal humans, each possessing the innate drive to exterminate the human race so their new race can thrive (though as the series progresses, this is called into question).

Etymology and declination
The name "diclonius" translates from Latin as "double sprout", referring to the horns which visually marks a member of the sub-species. The correct Latin plural would be "diclonii", but in the Japanese version, the plural is simply "diclonius" (since Japanese does not decline nouns in the plural), and this form carried over into the official English dub.

Emergence and Ostracization
Within the story, diclonius mutants have started being born to human parents only within the past few years, as a spontaneous evolutionary event. Because of their obvious physical differences from normal humans, diclonius children were shunned and ostracized by those around them, and often subjected to severe physical and mental abuse. A diclonius' vectors develop as early as when they are three years old, and at this age or soon after, they will use their vectors to attack those around them, including their own parents. Lucy is presented as being one of the first diclonius children active during this new evolutionary wave, as her attacks were among the first reported. Lucy first killed, provoked by years of bullying and trauma, when she was ten years old, eight years before the TV series begins. However, it would be another 5 years before Lucy was ultimately captured, during which time many other diclonius children also appeared (as well as Silpelit-Diclonius children created as a result of these original diclonius mutants infecting people with the diclonius virus, resulting in their children being diclonii).

The public at large is totally unaware that diclonius mutants actually exist. After the first sets of murders committed by diclonius children, such as Lucy, that appeared in the general population, the diclonius research institute headed by Kakuzawa began screening hospital maternity wards for new diclonius births, killing most of them while keeping a few for research. Those diclonii still alive in the general population, such as Lucy, were all eventually captured by the institute, also to be put under heavy restraint and subjected to inhumane medical research.

It is not known how many were kept alive for research purposes: Mariko was designated as "Number 35", so there may have been at least that many. In the manga, cloning of Diclonius was also mentioned, while only 4 of the clones were successful, others were killed and their body parts were recycled for further attempts at cloning. However, several diclonii have died in captivity (such as Number 3, who was killed during an escape attempt) so its unknown if there were exactly thirty-three other diclonii still alive besides Mariko. Also, Lucy is never shown to have been designated by a Number, and even research personal that refer to Mariko or Nana simply by number are seen referring to her only as "Lucy" (which itself might be a codename, as she never actually refers to herself as "Lucy," which is also likely because in the manga we find that her real name is "Kaede"). The "number" system was never explained, and it is possible that it referred only to Silpelits, and Diclonius "Queens" like Lucy may have either not been numbered, or referred to by a different set of numbers, etc. According to Episode 12 of the anime, it can be found that the number cycle may only relate to the Silpelits, as when Kouta runs to Nana, Kurama can be heard to say that it "looks like the boy may be an acquaintance of number seven's", leading us to believe that Nana was the seventh Silpelit, and so it may be that only Silpelits are numbered

It is revealed briefly in the anime series (but explained more fully in the manga) that some family lines of diclonii have actually existed for generations before the recent surge in diclonius births, keeping their identity a secret. However, interbreeding with humans has thinned out their bloodline and they cannot use their powers anymore, and only have small, vestigial horns (usually hid by wigs). Kakuzawa and his son are, in fact, members of a part-diclonius bloodline, and the secret goal of their research institute (hidden even from their head scientist, Kurama) was to find or develop a diclonius mutant that was capable of reproducing her babies in thousands, and then forcibly use her to mother a new race of diclonii, of which they would be kings. It is not clear if there were any more part-diclonii with genealogies extending back generations like that Kakuzawa family, or if they were the last of their kind.

Varieties
Diclonism can take many forms. It is possible for two normal human parents to give birth to a normal diclonius but such births are rare. Diclonism can also be spread via genetic infection contracted by direct contact of the Pineal gland with a vector; this more common form of procreation does not affect the human infected but causes any offspring of that person to be born as a "Silpelit", a sterile Diclonius variant, though some can still infect through their vectors. As generations of Silpelits progress, their hair and eyes take on a paler color from the previous one.

In the anime, all Diclonius born with vectors are females sharing the same physical traits of red or pink eyes and hair, though it is reasonable to assume that male Diclonius could also be born naturally, and share the same characteristics and powers as that of their female peers. The only male Diclonii shown in the anime were bald and had no apparent vectors due to interbreeding with humans continuously over generations. The high frequency of certain traits shared by all Diclonii suggests homogeneity in the Diclonius gene pool. Since interbreeding with human tends to decrease the frequency of these traits, the mutations caused by the Diclonius virus seem to be recessive to human genes over successive generations. In addition, since Diclonii could interbreed with humans, they should technically not be considered a separate biological species.

A diclonius born of human parents, sometimes described as the Queen Bees of Diclonii society, have life aspects similar to that of their human counterparts, aging at approximately the same rate and life expectancy at around the human norm. Silpelits are a subvariant of diclonius, described as Worker Bees, which age at twice the speed of normal humans and lack reproductive organs. Silpelits can seem mentally immature due to their rapid growth rate, but this is not the case: for example, the Silpelit Nana appears twelve years old, but behaves like a six year old, because she is actually six years old. This accelerated growth, when paired with their uncommon reproductive strategy, and the ability of Diclonii and Silpelits to sense -and to an unknown extent communicate with-each other, proves the Diclonii are a eusocial species. It is theorized that these silpelits are soldiers that will be used to exterminate the human race and allow full diclonii to reproduce and re-populate the planet. It is unknown if both parents are infected by a diclonius that the resulting child will be a full or silpelit member of the species.

The term silpelit comes from the German poem Elfenlied which in turn comes from the opera Eduard auf dem Seil.

Abilities
Although natural diclonii (as born from non-infected human parents) have the ability to reproduce, their range and amount of vectors appear to be inferior to those of the Silpelits. The character of Lucy, seen as the only natural diclonius in the series not to have been diluted with the human gene pool through interbreeding has a maximum vector range of two meters as opposed to the shortest silpelit range of three meters and the longest of eleven. This could be explained as natural diclonii are not warriors, with their vectors required only for infecting humans and been used as extra appendages, whereas the purpose of a silpelit is battle with the goal of extinction of an entire race. However, Lucy is the only natural Diclonius seen in the series, and only two Silpelits (Nana and Mariko) are described in detail, and they may not be representative of other Silpelits and Diclonii as a whole.

The seemingly supernatural power wielded by all diclonius comes from the vast development of the pineal gland (in a diclonius it is approximately the size of an egg ; in contrast, the human pineal gland is the size of a pea).

All diclonii share an extremely homicidal tendencies towards humans, occasionally bordering on sadism. According to Chief Kurama, a diclonius will attack and murder any human, including their own parents, from the age of three when their vectors begin to develop. Their eyes glaze over slightly and their pupils constrict when their killer instincts are active. However, it is debatable as to whether the homicidal tendencies shown by the diclonius are inborn, the result of harsh treatment from others during early development, or a side effect of their maturing vectors. In the anime, the various Diclonius characters exhibit various degrees of psychological instability. For example, Lucy's alter-ego, Nyu, is almost incapable of feeling any kind of violent tendencies toward anyone. Lucy, on the other hand, kills without regard for human life (although she does care for a few people, most notably Kouta and Kurama, even after her vectors are developed). Nana has a natural goodness that seems to be reinforced by Kurama, who treats her like his own daughter. So long as he treats her with care, she can deal with the pain of her testing. She becomes homicidal only when compelled to (to the point that when initially ordered to find and kill Lucy, she insisted on being allowed to merely subdue Lucy with non-lethal force, but her later attempt to kill her has much more fervor). It may be said that the homicidal tendencies are a result of an unstable psyche, itself a result of congenital recessive mutations, aggravated to such high levels by inhumane treatment from humans. Through the run of the series, the question is raised to the audience (but not answered) of whether the diclonius mutants' homicidal tendencies are an inborn drive to eradicate humans, or if (just like any "normal" human child) they developed this drive in response to years of physical and psychological abuse. It may be that the only difference between the diclonii and the human outcasts they resemble is that when angered, a diclonius can lash out with lethal force. The homicidal behavior observed in diclonii has only ever been directed towards normal humans; towards non-sapient animals (which do not pose a threat to them) diclonii can behave quite benevolently. This is exemplified in the anime when a young diclonius girl is shown killing a human for laughing at her, but when the human's dog attacks the diclonius and bites her hand, she does not think to harm the dog but reacts in shock and begins to cry uncontrollably.

Trivia

 * all Dicloni encountered in the anime have pink hair and are female, with the exception of Professor Kakuzawa and his father