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Deino Line

Morphs [Oak Catalog #]

  • Deino [633] (Cryptodraco melanoculus monocephalus)
  • Zweilous [634] (C. m. bicephalus)
  • Hydreigon [635] (C. m. cephalocheirus)

Physical Description

Deino is a small, quadrupedal, draconic creature that averages 80 centimeters tall and weighs in at a little over 15 kilograms, with females generally trending physically larger than males. Deino possess a stubby tail and a body covered in magenta scales around its shoulders and blue scales covering all other regions of its body, including its single-toed feet. Deino further possesses a coating of black protofeathers over its shoulders, neck and the back of the head. Said coating is especially dense at the top of the head, making a tall spike-like protrusion, and makes Deino appear to have a bowl cut, covering its presently underdeveloped eyes.


The second, bicephalic stage, Zweilous, increases in size and relative bulk, with typical individuals averaging 140 centimeters in height and 50 kilograms in weight. Zweilous adopts a sprawling posture after evolution, despite its limbs becoming stronger. Notable features of Zweilous' appearance include the emergence of two parallel rows of magenta scales on its belly along with the region on its shoulders, and the emergence of two distinct digits on its forelimbs. Zweilous also gains two protofeather covered wings that enable it to glide for short distances, as well as more clearly defined fangs, including a particularly prominent pair on its upper and lower jaws. Beyond expanding to accommodate its second head and its wings, the only major difference to Zweilous' region covered via protofeathers are that the spike-like tufts on top of its heads becomes bifurcated. As with Deino, the bulk of a Zweilous' body is covered in blue scales, its eyes on its heads remain underdeveloped, and its tail remains stubby.


The final, tricephalic stage, Hydreigon represents the most radical departure from Deino, dwarfing the original form by a full meter in height and almost 140 kilograms of additional bulk. Unlike both of its prior forms, Hydreigon is a bipedal creature, with legs with three claws each that have become mildly atrophied, hampering extended movement on the ground. This decline in the relative strength of its legs is compensated by the emergence of stronger and more numerous wings, with Hydreigon possessing 3 pairs, allowing for nimble flight and allowing it to remain airborne even if one or two of them become injured. In this stage, magenta scales cover a "fork" composed underside of the now lengthy and bladed tail with two "prongs" running along Hydreigon's belly, along with its shoulders and prominent crests on its heads composed of 5 spikes on the central head and 3 on its peripheral heads with the remainder covered in blue scales. A Hydreigon has 3 sets of eyes: The pair with red irises and gray-black sclera that occupies its central head is capable of seeing electromagnetic waves ranging from the Ultraviolet to the Infra-red portions of the spectrum, the eyes with black sclera without defined irises on its left and right heads are similarly, though not as underdeveloped as those of Deino and Zweilous, and appear to be capable of sensing movement. Hydreigon's protofeather covering also changes, covering additional pairs of wings and extending further along its back and small protofeathers near the blade of its tail. In addition, the pattern of pseudofeathers that has remained relatively constant through Deino's evolution into Zweilous becomes more varied: The central head is fully exposed, with an overall structure not wholly removed from that of Sceptile's, while the peripheral heads retain a protofeather coat more analogous in appearance to that of the heads of the earlier forms.


In exceedingly rare cases, individuals from this line are known to carry a mutant phenotype. Possessors of this mutant phenotype have slightly lighter-colored protofeathers, as well as green and violet scales in regions where blue and magenta regions normally occur. These creatures are highly sought after in some circles, and are known to command a hefty premium on the black market.

Notable Biology

One of the most striking features of this line of Pokemon is the anatomy and development of its nervous system:

Deino’s brain has two key chacteristics: First, there is no crossing-over of nervous pathaways: The right hemisphere of the brain controls the right side of the body; the left hemisphere controls the left side. The same applies to the (poorly developed) eyes: There is no optic chiasm. The other important character is that both hemispheres send down, alongside the spinal cord, axons normally found in the corpus callosum in other creatures. Those axons meet in an associative ganglion, found at shoulder level, surrounding the spinal cord before the thickening of said structure in the area where nerves controlling the arms leave it, and protected by an enlargement of the first dorsal vertebrae (due to the bodies of this line being quite compact, this shows no noticeable effect on movility), process the information, and send it to the opposite cerebral hemisphere it came from. Said ganglion also innerves two areas, each between the shoulder and the neck, under the coat, which contain accessory (and most of the time closed) respiratory openings, and invaginations of the stomach that produce extra quantities of enzymes and acid if the meal Deino consumed was particularly large. The neurons of this Pokémon also show remarkable plasticity, and generalized ability to duplicate if the need arises, as well as a solid gliar system.

Zweilous' nervous system is defined by each of its heads containing half of a larger brain, left or right hemispheres (as well as left or right basal ganglia, midbrain, cerebellum and medulla). The hypothalamus, hypophysis and pineal gland are localized in a single head, but the other half of the brain still has connections with the hypothalamus thanks to the neck ganglion. The hearing of Zwelious is one of the best of all Pokémon, thanks to each head having two ears and therefore an increased contrasting ability. It is still blind, and in the rare case the eyes are seen, each head has only one, with the other socket housing a pineal gland and being sealed closed. While the heads harbor distinct, and often competing personalities, which results in Zwelious often eating too much, they form a single collective individual that will readily coordinate to deal with would-be antagonizers.

Contrary to what an initial impression and Zweilous' nature would suggest, Hydreigon do not normally have distinct personalities. It is presently unclear whether this is due to one of the personalities from the individual's period as a Zweilous emerging dominant, or whether this state is the result of a fusion of personalities. In this stage, the innervated spots Hydreigon already possessed in its shoulders when it was a Deino develop into pseudo-heads, complete with eyes, ears and noses, as well as mouth and both respiratory and digestive access. However, such heads only have a coordinative ganglion instead of a brain, and it is up to the large neck ganglion to process the information those “heads” receive to a Hydreigon's brain, located in the central head, and to respond to signals from the brain dictating how to react to different stimuli.

Another notable element of the biology of this Pokémon is the time it takes to grow out of the Deino stage, best shown in an experiment done as part of an extensive study by several professionals: A Deino was raised alongside a Dratini, a Larvitar, a Bagon and a Gible, under equal and favorable conditions and receiving equal and favorable treatment. While the growth rate of all five Pokémon seemed to be the same, and the other four, also stages of pseudo-legendary Pokémon, are notorious late-evolvers, Deino didn’t evolve into Zwelious until after Gible had completed its evolution into Garchomp, and about the same time Bagon completed its evolution into Salamence. Dratini and Larvitar were still at the Dragonair and Pupitar stages at that point, respectively, but finished their development soon afterwards, while Zwelious took a bit longer to become Hydreigon. Still, despite what others were lead to belive, said evolution did not require any special circumstance, only time and training, disproving beliefs in the same way the truth about the evolution of Larvesta was discovered. During the experiment, the Deino appeared to possess remarkably poor relations with the Larvesta, Larvitar, and Axew as they matured. As the only behavior recorded with precedence was the poor interactions with the Axew, due to the natural rivalry that the two possess between populations in Unova, it was spurred a great deal of debate in some circles as to whether the Deino's interactions with the Larvesta and Larvitar were an isolated incident, or indicative of a recurring phenomenon.

All stages of this line possess heightened senses of smell, touch, and hearing, and are capable of perceiving stimuli of such natures that most Pokemon would be incapable of noticing reliably. In addition, these creatures appear to be capable of discerning minute changes in smell and sound, the latter of which is particularly developed, as creatures from this line have been demonstrated to discern sub 10 decibel noises in the midst of 100 decibel ambient noise as well as to discern objects via what appears to be a form of echolocation involving shrill calls. Despite this, Deino and Zweilous are known to be susceptible to being disoriented via stimuli, which occasionally leads to these creatures narrowly missing their opponents in a battle setting with their attacks.

Like many other Pokemon, creatures from this line possess structures conducive to generating and setting alight incendiary gases generated via the digestive tract. As Deino and Zweilous, these structures are used for occasional incendiary bursts, but generally do not see extensive use until the Hydreigon stage has been attained on account of sight aiding the process of targeting prey. Unlike most other creatures immediately related to it, these structures among Deino line members appear to be outgrowths of what was once an omni-sac, with vestigial components that facilitate electrogenic and cryogenic behavior. With extensive training, it is possible to teach Hydreigon how to utilize those vestigial components of its omni-sac for a narrow range of techniques.


All stages of this line appear to dwell in mountainous regions. Deino and Zwelious are usually cave-dwellers, employing their well-developed hearing to prowl passageways stalking their prey. Creatures from this line appear to be capable of living in subterranean chambers of all sizes, though seem to fare especially well in small spaces with plenty of points from which to ambush prey. Hydreigon tend to have a greater openness to non-cavernous environments, and will often travel via air to prey on creatures living in valleys and plains below the mountains in which they reside.

Stable populations of Deino and its evolutions appear to be exceedingly rare, with one of the few such populations known to presently exist located in the general vicinity of Unova and Kalos' Victory Roads. It appears that Deino and its evolutions may have once had a vastly larger range, as accounts of encounters with creatures from this line exist in folklore from throughout Unova. Curiously, there is some evidence suggesting that these creatures may have at one point had a presence in the broader portion of the world that hosts Kanto, Johto, Sinnoh, and Hoenn, suggested by anecdotal accounts of encounters with creatures whose descriptions are consistent with those of creatures from this line, as well as an uncanny similarity between Deino and its evolutions and a widely-reviled figure in those regions' folklore. Within Hoenn, the Deino line has recently returned due to the awakening of the super ancient Pokémon, mainly making its home within Meteor Falls.


Creatures from the Deino line trend heavily carnivorous, though have been known to readily consume plant matter, if on an infrequent basis. Creatures from this line have metabolisms that are incredibly fast by reptilian standards, eclipsing that of even members of the Machop line, and are known to have a rather liberal attitude towards what is considered "edible." All stages engage in both active hunting and scavenging as a means of sustenance, with Zweilous and Hydreigon trending more to the former, and will readily consume creatures smaller than them that lack the presence of toxins, an excessively durable hide, or otherwise do not pose an existential threat. Like Salamence, Hydreigon are said to feed on their younger brethren. Unlike Salamence, this practice has been reliably recorded outside of folklore, and appears to extend over to some of the initial forms of other draconic Pokemon. It has been noted that members of this line are capable of metabolizing foods high in refined sugars, though given the effect that this has on many Pokemon that are capable of such a feat, it is generally not recommended to attempt this with creatures as powerful as Deino and its brethren.

The preferred prey of Deino appears to depend upon the relative availability of prey. Amongst individuals hailing from Unova's Victory Road, Woobat appears to be the preferred prey of Deino, due in no small part to Deino being immune to its prey's psychic attacks. Deino from this region have also been recorded to readily attack Heatmor and scavenge Durant. Zweilous from this region will take on larger prey such as Swoobat, while Hydreigon from this area appear to be fine with whatever prey they can find, but appear fairly fond of Braviary and Mandibuzz.


Although their designations as the Irate, the Hostile, and the Brutal Pokemon are perhaps oversimplified and have long been a point of contention amongst some circles of trainers who argue that such designations serve only to reinforce unjust stereotypes, it should go without saying that unduly antagonizing Deino and its evolutions is an exercise for trainers yearning to dramatically shorten their life expectancies. The initial two stages of the Deino line, Deino and Zweilous, generally specialize in melee attacks. Both forms are known to use a variety of biting, clawing, and tackling attacks, which depending upon the technique and relative strength of the user, are capable of leaving anything from simple puncture wounds to gashes deep enough to cause massive blood loss and causing anything from moderate bruising to breaking multiple bones and causing massive internal bleeding. Both of these forms are also capable of utilizing incendiary breath attacks, which are capable of inflicting second and third-degree burns. Beyond all of this, some creatures from this line of particular lineages have been known to exhibit command over paranormal phenomena exhibited by other Dark-Types, most notably the technique known as "Dark Pulse."

Although they have been known to exhibit loyalty to their trainers to the point of death, Hydreigon are truly in a class of its own relative to its prior two forms in terms of raw destructive potential. Beyond the techniques that it was capable of using as a Deino and a Zweilous, a Hydreigon will have additionally developed a long, prominent tail that can serve as an implement with which to slash and stab at foes, and possesses a much greater precision with its attacks thanks to the addition of sight along with its formidable senses of hearing, feeling, and smell. Beyond these melee techniques are a number of other ranged techniques, which are no less threatening. Like its younger brethren, Hydreigon are capable of using incendiary breath attacks, though generally are vastly more competent in their execution of said attacks In addition, Hydreigon also utilize techniques involving deafening roars to stun and disorient prey, which is capable of causing temporary, and in some cases, permanent hearing damage. Captive Hydreigon also are known to be capable of being taught some techniques that pose hazards to those foolhardy enough to antagonize the creatures, including the ability to utilize attacks that combine incendiary, cyronic, and electric bursts, as well as the ability to generate large waves of water via the technique typically referred to as "Surf" to knock foes down. Irate Hydreigon are known to be particularly hazardous, and have been known to enter frenzied states not wholly unlike those that are sometimes recorded amongst Salamence. Due to their immense strength and often aggressive temperament, it is not unknown for matches involving Hydreigon to result with its hapless opponent becoming seriously injured or killed. Because of this, a number of smaller leagues and tournaments have barred these creatures from participating in their tournaments, with the Indigo and Sinnoh Leagues presently undergoing a review of the battle-worthiness of these creatures. As of present Hydreigon remain legal to use in events sanctioned by the Hoenn, Unova, Kalos, and Alola Leagues.

If one has the misfortune to encounter an irate Deino line member, it is generally recommended to flee rather than to fight. As with other cases, Repel is one of the most immediately useful means for securing time for escape, and with creatures such as Deino and Zweilous that are forced to rely on limited sensory inputs, is a particularly potent tool. Techniques focusing on forcing Pokemon away such as Whirlwind, or failing that, on inducing paralysis are also viable options for buying time for an escape. If all else fails, attempt to mollify the irate Deino line member with offerings of food, while trying to remain inconspicuous as possible, a technique that is also valuable for calming down upset Pokemon from this line in captivity. It should be noted that this measure is by all means a situational and last resort, and if the creature from this line is particularly offended, you may find it more useful to pray to any relevant deities that you somehow best the creature in direct battle.

Other hazards related to creatures from this line include the deceptive appearances of the members of the first morph. It should be kept in mind that for the bulk of its life, a creature from this line will retain the form of a Deino, which beyond subtle size differences and the relative abundance of wounds from sparring makes discerning the age of particular individuals difficult, and the strength of such individuals even less immediately obvious, a characteristic which has led to the hospitalization if not the demise of many an unwise trainer. It should be noted that young Deino possesses an instinctive biting response to stimuli not wholly unlike that of Totodile, which will quickly lead to injuries and the destruction of personal effects if not trained to suppress such behaviors. Coupling along with this response is the general tendency for creatures of this line to view creatures perceptibly smaller than themselves as potential prey, which if not countered while still a Deino, will make training an individual as a Zweilous exceedingly difficult, and training as a Hydreigon virtually impossible. Creatures from this line are known to be difficult to control during captive breeding, due to the particularly strong maternal behaviors that creatures from this line exhibit, which is particularly dangerous for individuals that have attained the Zweilous and especially the Hydreigon stages. It should also be noted that the Zweilous stage, while far from the most hazardous stage to care for, is perhaps the most demanding. As the independent heads are known to frequently vie for control over the body as a whole and quarrel with each other. Some trainers have found the use of a "headpuppet" doubling as a muzzle helpful to prevent a Zweilous from overly harming itself.

Courting and Childrearing

All stages of this line are fertile, with mating amongst Deino being the most commonly documented occurrence by virtue of Deino's relative abundance compared to Zweilous and Hydreigon. In all stages, courtship appears to be virtually non-existent in the wild, with most behaviors recorded around mating amongst members of this line consistent with opportunistic practices exhibited by Pokemon such as Tyranitar. After mating, a male and female from this line will separate, the female laying a clutch of eggs roughly a week after if her eggs are successfully fertilized.

Deino typically lay single eggs, whereas Zweilous and Hydreigon typically lay clutches of 2-3 and 3-5 eggs respectively. Unlike most Pokemon of their ecological niche, members of the Deino line appear to be fairly fecund, as a majority of encounters between mating individuals will yield young. Deino eggs typically hatch over the course of two weeks, and are jealously guarded by their mothers. Once they hatch, the newborn Deino will imprint on each other and on their mother, who feeds and cares for them for the first 6-8 months of their lives. Afterwards, the Deino will go separate ways, and likely won’t have any meaningful interactions with others of their kind until they look for a mate.

Social Structure

Deino's line is known to be generally asocial, with later morphs trending increasingly territorial. Deino generally do not retain intimate ties with counterparts from their line beyond the first 6-8 months of their lives, during which Deino will be cared for by their mothers and taught how to hunt. After leaving or otherwise being driven from their mother's den, Deino typically lead solitary existences, though do not appear averse to interacting with other Deino, especially if food is involved. Upon evolving into Zweilous, these creatures generally become more territorial, and will become openly hostile towards individuals of the same gender, towards Deino that are not its own young, and will typically act similarly hostile to any creature that is not a potential mate, a close acquaintance, or is otherwise something that the Zweilous was socialized with as a Deino, a behavior that carries over to the Hydreigon stage if attained. This territoriality appears to be less pronounced when sources of food are particularly abundant, as a small number of settlements near Opelucid City in Unova are known to be in close proximity to stable (if small) populations of creatures from this line, and are one of the few settings outside of captivity where Zweilous and Hydreigon are known to dampen typical hostilities towards entities that would typically be attacked in other settings.

Interactions with other creatures in the wild beyond the occasional curious examination generally fall into the rough categories of "prey" and "predator" interactions. Deino and its evolutions will typically view smaller creatures as potential meals, barring exceptions that pose an immediate threat to their well-being or are otherwise known to be inedible, and generally trend averse of larger creatures, a behavior not wholly unlike that exhibited by some populations of Pokemon in their natural environment such as the Totodile line. It should be noted that this behavior appears to be innate to an extent, as even egg-hatched Deino appear to exhibit behaviors that are analogous to, if not as pronounced as those of their wild counterparts.

In Human Culture

In most cultures that have had contact with these creatures, members of the Deino line are more have more or less possessed pariah status, rarely seeing depictions mounting to more than as mindless, heartless engines of destruction hellbent on devouring the world around them. All stages were reviled for their predation of livestock, as well as their greater propensity to feed off of human beings than similarly demonized Pokemon. These accounts are further exacerbated by (in all likelihood exaggerated) anecdotal incidents, including one alleged case in which a member of this line systematically killed off the bulk of the crew members aboard an ore freighter, and another where a group of poachers that destroyed a clutch of eggs in front of its mother were supposedly stalked a fair distance before one of their number was abruptly impaled by the irate Hydreigon's tail, and then torn into two. It is theorized that either direct or indirect contact with these creatures may have been the origin of a number of monstrous or evil entities in folklore, one proposed tie being a multi-headed beast that occasionally appears in folklore in Johto and other regions in relatively close proximity.

Despite its demonization in many of the cultures that have had contact with them, members of the Deino line occasionally saw applications within the human societies that encountered them. The bulk of these applications were military in nature, focusing on Hydreigon providing aerial support to under the command of a handler against opposing forces. It should be noted that folklore surrounding the use of Hydreigon within battle typically saw praise being directed towards the creatures' handlers as opposed to the creatures themselves when they were allied, and when fielded by foes, often are used as a symbol with which to collectively compare enemies to and demonize. Another, widely-reviled application that Deino members saw in historical societies was their use as an execution method, most notably in some Unovan noble circles, not wholly unlike a similar practice involving Tynamo line members. Other, less prominent, but more benign applications that these creatures saw in human society included use as garbage disposals and pest controllers. A handful of communities in Unova, mostly around what is now Greater Opelucid, also had histories of encouraging small populations of Deino line members to dwell in close proximity via regular feedings, which continue in some communities to the present day. It is theorized that the practice may have been originated as a defense mechanism in order to ward off marauding armies.

In modern media, Deino and its evolutions' historically poor perception in most human societies continues to color its depictions. Deino and its evolutions, most notably its final form, Hydreigon appear as antagonistic figures in a truly astonishing number of works. Some of the most prominent of these appearances include an unusually large Hydreigon serving as a generally unsympathetic rival to a unusually large Tyranitar in a long-running film series, as recurring enemies in video and tabletop games, two of the more recent depictions including as a recurring enemy in an installment of a long-running action-adventure video game franchise, and as a model for a boss from an action adventure game set in a world heavily influenced by Johtoan folklore. Although Deino and its evolutions have possessed a subtle dampening of traditional vitriol heaped upon the creatures in most historical depictions, outright sympathetic portrayals are virtually non-existent, all of which appear to have followed the wake of the rise to popularity of a rock band whose members wore hairdos remarkably similar to that of Deino's head protofeathers. In Unova, media depictions of Deino and its evolutions appear to have hit a recent nadir, due in no small part to the highly-publicized attempted hacking of the region's PC system and coup d'etat masterminded by prominent Unova Hydreigon trainer Ghetsis Harmonia, which was noted to have attained its final form unusually early under currently unknown circumstances.

Original Article by Eriorguez. 1/2012 Revision by Tracer Bullet.


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