X-Antibody

The X-Antibody (X抗体 Ekkusu-kōtai) is an that, when present in a Digimon's Digicore, provides them with resistance against the effects of Program X. If it is present in high enough concentrations, it is also able to cause a Digimon to undergo X-Evolution into an X-Antibody-enhanced form with new or improved traits.

=Overview=

Origins
The X-Antibody originated with Program X, a tool used in Project Ark to cull Digimon and end the overpopulation of the Old Digital World. However, powerful Digimon with strong survival instincts were able to survive by altering their Digicores to incorporate Program X itself. This created the X-Antibody, which made them resistant to being deleted by Program X. However, since the X-Antibody in a Digimon's Digicore would expire if the Digimon continued to be exposed to Program X, this resulted in two major societal societal shifts: first, competing with each other to acquire more X-Antibodies, and second, an exodus of Digimon from the Old Digital World to the New Digital World, where Program X was not present.

Acquisition
There are three main ways for a Digimon to acquire the X-Antibody.
 * When exposed to/infected with Program X, alter their Digicore to incorporate Program X into it. Only strong Digimon are able to do this.
 * Kill and absorb the data of a Digimon who already possesses the X-Antibody. There is intense survival-of-the-fittest competition between Digimon for X-Antibodies, and weaker X-Antibody Digimon (such as Tokomon (X-Antibody), a rare case of a Baby X-Antibody Digimon) are often preyed upon as easy targets.
 * Receive a serum of the persistent strain of the X-Antibody.

Temporary Nature
In its original strain, the X-Antibody population within a Digimon who acquires it is not permanent. They must continue to intake more X-Antibodies in order to maintain the X-Antibody within themselves. In particular, continuous exposure to Program X will destroy a Digimon's X-Antibody population, again unless they intake more X-Antibodies.

This restriction does not apply to Digimon who naturally possess the X-Antibody, such as Alphamon, Tobucatmon, and Metalpiranhmon. The X-Antibody strain that they carry does not disappear from their bodies.

The deaths of Digimon who carried the X-Antibody have resulted in the mutation of another, persistent strain. When an X-Antibody Digimon dies and is sent to the Dark Area, they have been known to leave behind the data of duplicate X-Antibodies as residue. Originally, such duplicates would quickly cease to exist. However, over time, the strong survival instincts in the Digicores of the carrier Digimon caused these X-Antibody particles themselves to acquire self-preservation functionality, resulting in a persistent strain of X-Antibody that does not require its host to continue to intake more X-Antibodies. The persistent strain can be acquired by absorbing the data of a Digimon who innately carries it, or it can be administered as a serum to a Digimon.

X-Antibody Concentration Levels
The effects of this antibody differ depending on the concentration of antibodies present on the Digicore. There are three levels of concentration.

The presence and concentration of the X-Antibody in a Digimon can be identified by the X-Antibody Indicator (XAI) system invented by Yggdrasil. This system would later be implemented on the Digimon Pendulum X and Digital Monster X devices.

Resistance to Program X
Any concentration level of the X-Antibody within a Digimon's Digicore is sufficient to protect them from the effects of Program X, in the same way that a real protects an individual from a particular foreign pathogen.

X-Evolution
The X-Antibody has the ability to, if concentrated within a Digicore at normal level or higher, actively extract latent data from the Digicore to a high degree. When this happens, it triggers X-Evolution (ゼヴォリューション Zevoryūshon/X-進化 Ekkusu-shinka), where the Digimon is transformed into a form that expresses that extracted data. As a result of this, the Digimon becomes able to express both power and its potential to a degree far superior to a common Digimon.

Typically, X-Evolved variants of pre-existing Digimon are distinguished from the regular variants by the suffix "X-Antibody", in parentheses, at the end of their name. For example, a Gomamon who has undergone X-Evolution is called "Gomamon (X-Antibody)" 「ゴマモン（X抗体）」. This is sometimes shortened to just the letter "X" (for example, "Gomamon X" 「ゴマモンX」).

The nature of what X-Evolution does to a Digimon is entirely dependent on what, and how much, latent data they have for the X-Antibody to extract. In addition to a common increase in the Digimon's power and potential, effects include:

If a Digimon simply does not have much latent data that its original form was not previously expressing, X-Evolution will not cause much change in them. For example, the relatively minor changes that Holydramon and Goddramon undergo when they X-Evolve into Holydramon (X-Antibody) and Goddramon (X-Antibody) indicate that the two Digimon had already been expressing their latent data and abilities in their original forms.

A side effect of X-Evolution is that any wounds the Digimon had prior to the X-Evolution are healed, and their stamina is replenished.

Other Effects
X-Antibody Digimon can bypass the XSpiral's "X-Barrier" entirely and deal regular damage, in addition to taking 25% less damage from the XSpiral's "X-Charge". However, this is only applicable to Digimon like War Greymon (X-Antibody), and not natural carriers like Alphamon.

Death-X-Evolution

 * Main article: Death-X

Related to the X-Antibody is the phenomenon of Death-X, in which the X-Antibody forces a Digimon to keep evolving even after it has died, in a process called Death-X-Evolution. A Digimon who has undergone Death-X-Evolution remains active and animated despite being deceased and despite the decay of its own body, and it is governed by a powerful instinct to consume Digicores so that it may continue to evolve and remain active.

Digimon normally have no access to Death-X-Evolution by themselves. It can only be triggered by a third party that knows how it works, like Yggdrasill or Grand Dracumon.

=Appearances=

Digimon World X is based on the history of the X-Antibody. In the game, the X-Antibody can be used to increase the powers of Digimon as well as objects.

In the Digital Monster Card Game, cards depicting Digimon who possess the X-Antibody are identified as such by their red frame (as opposed to the blue, gold, or silver frames used by other cards). The red frame is regularly cited as a necessary criterion in cards' Evolution/Fusion/Appearance Requirements for evolution into or from X-Antibody Digimon, and in some cards' Special Abilities that target X-Antibody Digimon in some way.

Option Cards relating to the X-Antibody and the related story also have the red frame.

In the Digimon Card Game, Digimon who possess the X-Antibody are identified as such by the listing of an "X-Antibody" property in the Digimon's Type. The X-Antibody's own card also lists this property. The property is cited as a necessary criterion in the effects of Digimon and Option Cards that in some way relate to or target X-Antibody Digimon.

=Image Gallery=

=Additional Information=