The X-Antibody (Ｘ抗体 X-Kōtai?), stylized in some materials as X Antibody or X Anti-body, is a plot element from Digital Monster X-Evolution, Digimon Chronicle, Digimon Chronicle X, Digimon D-Cyber, and the related virtual pets and card games. It is a vaccine that makes Digimon immune to the X-Program, and most Digimon that are introduced to it also become more powerful than their normal counterparts; they are differentiated from their original forms by the suffix "X" or "X-Antibody". There are also many species of Digimon who are natural carriers of the X-Antibody, and do not have a separate "original form".
Digimon Pendulum X / Digital Monster X / Digimon Chronicle
When the Digital World became so overpopulated, the super computer that governs the Digital World, King Drasil, wasn't able to handle it anymore. His solution was to wipe out the vast majority of the Digimon with the X-Program, and choose a very small percentage to be moved to a new Digital World, and destroy the old one. Those who were not chosen but still survived and moved to the new world had a rare gift known as the X-Antibody. This antibody, when activated, changed their appearance and strength. The X-Antibody Indicator (Ｘ抗体インジケーター X-Kōtai Indikētā?), also referred to as the XAI System (ＸＡＩシステム Sai Shisutemu?) is a system which displays the status of the X-Antibodies. If the XAI system is activated, via the Pendulum X, and it detects the X-Antibody present, it will begin to alter the Digimon itself, resulting in an X-Antibody Digimon.
Digital Monster X-Evolution
The X-Program (Ｘプログラム X-Puroguramu?) is a termination program initiated by King Drasil to eliminate 98% of Digimon as a result of the exponential growth of Digimon causing the Digital World to reach maximum capacity. When the X-Program was executed by King Drasil, 98% of the total Digimon population was eliminated. The remaining 2% were transferred to the NEW Digital World where the X-Program could not reach them. However, a minority number of Digimon strong enough to resist the effects of the X-Program were able to survive by changing their DigiCores. The Digimon were reborn in a form that could take in the X-Program and eventually it came to a point where a program that opposed the X-Program was installed into the DigiCore—the X-Antibody.
All extant Digimon are X Digimon.
Digimon World Re:Digitize
X-Antibody variants of Digimon (ex. WarGreymon X but not Alphamon) are able to ignore the "X-Barrier" that X-Spiral have access to in addition to taking 25% less damage from the X-Spiral's "X-Charge" attack.
Digimon Collectible Card Game
List of X-Antibody carriers
On August 10, 2021 the Digimon Reference Book added the X-Antibody to Digimon's profiles, re-confirming them as Digimon with the X-Antibody — however they did not include it for ClavisAngemon, Dexmon, Dracmon, GranDracmon, Matadormon, Sangloupmon, MedievalGallantmon, and Volcdramon. Whether this is a mistake, or is Bandai retconning them to no longer having the X-Antibody is unconfirmed. They are all stated to be X-Antibody carriers in Digimon Masters and/or the Digital Monster Card Game.
- Natural carriers
- Other carriers