Dark Chip

Dark Chips are vastly powerful Battle Chips created by Dr. Regal, that increase a NetNavi's power beyond limits, but destroys the Navi's connection with its NetOp and turns them into a Dark Soul Navi, or even Darkloids which use these chips to survive. They start out using them to become more powerful, but soon become addicted and need them. After a while of addiction, it starts to corrupt their data, until eventually they become so corrupted that they are deleted. In the anime, Dr. Hikari states that the Dark Chips are a type of chip which trades a Navi's soul for power (sort of like "a deal with the devil").

Dark Chips can be strongly compared to drug addiction in both the games and anime in many ways. Interestingly, MegaMan can control Dark Chip influence if used, but an overload of dark energy like a Dark Chip implant or a direct infusion of dark energy will cause him to turn into MegaMan DS, who also cannot die from Dark Chip use, due to the fact he was born from pure dark energy.

In the games
In MegaMan Battle Network 4, Dark Chips can only be used when MegaMan enters an "anxious" state, after taking several hits in succession without fighting back. They will take up the last two slots of the Custom Screen, and cannot be used with any other chip, aside from another Dark Chip. When one is "dark" enough, he can enter the battle with Dark Chips already displayed. In MegaMan Battle Network 5, the Dark Chips are Battle Chips on their own, with their own code. Each folder can hold up to three Dark Chips at one time.

Dark Chips are the most powerful chips in both games if the player used them frequently, but the glitches they cause can discourage players from using some of them. Chaos Unison bypasses the glitch, but with a twist, so it is also rather ineffective, unless the player needs to reuse a Soul Unison, as the same Chaos Unison and Soul Unison can be used in the same battle.

In the anime
The chips simply power up whatever NetNavi uses them (however, it is later shown there are still dark versions of chips like Dark Sword and Dark Cannon), but they still turn them evil. Another side effect, likely created to coincide with the fact they permanently remove HP in the games, is that over time they delete the data of whatever NetNavi uses them. The Dark Chips were also exceedingly addictive. ProtoMan turned evil in episode 27 of Axess after Chaud slotted in an extra strong Dark Chip to fight ShadeMan, though later a cure was found.

Effects
Dark Chips have several effects:
 * When any number of Dark Chips have been used in battle, the user permanently loses 1 HP from their maximum HP count until only 1 HP is left.


 * Using a Dark Chip will result in a bug occurring in MegaMan, depending on the Dark Chip used (though most have the tendency to cause an HP bug).


 * When MegaMan has used enough Dark Chips, he turns "dark" becoming the entity which is known as DarkMega or MegaMan DS, losing the ability to enter Full Synchro or use Double Souls. He also gains the ability to use chips exclusive only to "dark" MegaMan (like Muramasa), DS Chips, and will enter a "berserker" state on a lethal hit. To reverse the effects of "darkness", one must enter battles without the usage of Dark Chips, and this process can be sped up by the "Soul Cleanser" NCP.

List of Dark Chips (excluding DS chips)
In both Battle Network 4, Dark Chips always have the same description: "DARKCHIP CREATED BY DESIRE" (In caps). Additionally, there are chips that can be only used while "Dark". These chips are normally tagged with "Evil Chip!" in the description, and are normally powered up versions of their predecessors. Most are Mega Chips, preventing a player from completely building a folder around these chips.

*In Battle Network 5, some Dark Chips were removed to compensate for others and each chip can be used for a Chaos Unison.

Obtaining
There are four ways to obtain Dark Chips:
 * 1) Enter the "Worried" or "Dark" state. (MMBN4)
 * 2) Buy them from people who say they have "a really rare/powerful/alternate-colored chip". (MMBN5)
 * 3) Use the Lotto Number. (Certain types only in MMBN5)
 * 4) Find them in Certain Mystery Data. (MMBN5)

Trivia

 * Intense hacking in Battle Network 6 will reveal that Dark Chips were planned to be used (and this time, did not remove HP or cause a Dark State, but inflicting an extremely fast HP bug), but the ideas seemed to have been scrapped, seeing as there are no descriptions for some chips and no icons for any Dark Chip in that game. However, the chips work fluidly and do not freeze the game.
 * Dark Sword and Dark Thunder made a return as BugRSword (Bug Rise Sword) and BugThunder (Bug Death Thunder), which when used, replace MegaMan's Charge Shot at the cost of sacrificing bugs (both are Giga Chips).
 * In Japan, one can use toy Dark Chips with the Battle Network 6 Beast Link Gate to download Dark Chips, inflicting the above bugs. This does not apply to Battle Network 5 normal Battle Chips, but the player can slot in chips from the opposite version of Battle Network 6.
 * Chaud, in both the anime and Battle Network 4, has resorted to using a Dark Chip on ProtoMan when backed into a corner; both instances led ProtoMan to be consumed by a powerful Dark Soul, though he curiously shows no physical detriment after being freed.
 * Chaos Unisons are a safe way to use dark chips; players will just have to watch out for the charge shot.
 * However, an exploit exists to ensure that there are truly no consequences from using a Chaos Unison: If the player pauses the game during the charge shot, they can see if the shot is currently "good" or "bad". The button can be released before unpausing in the former case to use the attack risk-free; in the latter case, the player will simply unpause without releasing the button and repeat the process until the "good" charge shot is found.
 * The only time dark chips are allowed is when fighting ShadeMan in Castillo, they won't cause bugs.
 * There is a chip in the MegaManNT Warrior anime which works similar to a Dark Chip. It is called Super Great White Angel or Devil Chip. As a Dark Chip it makes Net Navi more powerful and evil, however, it does not addict and corrupt the Navi like the normal Dark Chip. (This Chip was given to Mayl by Yahoot disguised as Higsby).