A horde of Batty and Sparky viruses.

A Virus (ウィルス) is a malicious or corrupted program that disrupts the operating system or cyber network of electronic devices. Viruses are encountered as enemies in the Mega Man Battle Network series, found randomly across the cyberspace (serving as an analogous of monster random encounters in many RPGs), searching for NetNavis and other programs to delete or mess with.

A NetNavi must thus have basic Virus Busting abilities to navigate safely on the Internet, otherwise its actions will be limited. Viruses may leave Battle Chip data upon deletion, the chip depending on the virus, and related to the attack that the virus uses.


While viruses are often wild, some are man-made. Despite the common belief of their negative and hostile nature, viruses are not inherently evil, but rather are most of the time a program with a very basic inclination for mischief and as such are a major nuisance to everyday life. However they can be quite utilitarian for societal functioning needs, as some are created to guard important data or switches. Criminals often use viruses to trap data in an attempt to delete (or at least stall) Navis that may be trying to stop them. They are also commonly used by villains to shut down machinery.

In Mega Man Battle Network 3, MegaMan is capable of calling a virus to launch an attack against an enemy. In this game it is revealed that there a handful of viruses who are friendly and can be tamed (although several of them must be rendered non-hostile through battle before settling down). Such viruses, although a rarity, are placed in the Virus Breeder and can be raised and managed, very much like pets. Doing so allows MegaMan to acquire special chips which is how he can summon them in battle.

Other NetNavis are also capable of calling viruses for use in battle. An example is MagicMan in the first Mega Man Battle Network, but also HeelNavis commonly use viruses to attack their opponents (although they often use viruses to do all of their fighting, some that fight in battle themselves are capable of calling viruses mid-battle). Roll.EXE also has the ability to summon viruses to aid her. Rush and Trill are also capable of calling viruses in the MegaMan NT Warrior anime series. However, it is unknown whether they were properly capable of taming viruses in a manner similar to MegaMan, that is to befriend them, or if they purely take control of the viruses through some external programming, although given the Virus Breeder limited appearance, the latter seems the most likely.

In the anime, some Battle Chips can summon a virus to execute an attack. For example: Cannon chips are used to summon independent Canodumb viruses controlled by the operator, Condor summons a Fishy3 to ride on, IceBall can summon a ColdHead that fires a frozen cannonball, and Trident summons a Piranha to fire a trident spear.

As such viruses can be severely detrimental to society, but they can have an equal ability for contribution. As such their utility is directly proportional to its user.

Besides combat, viruses can also be used for practical purposes. For example. in Mega Man Battle Network 4 Red Sun, Mr. Match used a fire virus to improve a fryer.

Virus list

The Mega Man Battle Network series has over 100 different viruses.

See also