Shadow Pokémon

Shadow Pokémon (ダークポケモン, Dark Pokémon?) were Pokémon that were used for wrongful acts because they had the doors to their hearts shut artificially, a process created and carried out by Cipher in the Orre region. They were temporarily wiped out by the combined efforts of Wes, Rui, and Michael, but are still being produced by Cipher.

Creation and behavior
Shadow Pokémon were created through an undisclosed process that removed the Pokémon's emotions, turning it into a soulless fighting machine. Ein, creator of the process and Cipher's head scientist at the time of Pokémon Colosseum, refers to this process as "shutting the door to their hearts". In Pokémon XD: Gale of Darkness, Cipher's science division refines and upgrades the process, allowing many Shadow Pokémon to be produced simultaneously. The head of the science division, Cipher Admin Lovrina, also worked on stabilizing the process to increase resistance to purification; her ultimate goal is to create a Shadow Pokémon that is completely impossible to purify.

While normal Pokémon are generally friendly and trusting creatures, Shadow Pokémon are not hesitant to attack with full force, using Shadow moves, such as Shadow Rush. Likewise, they do not attack only other Pokémon, and will actually attack Trainers when in Hyper Mode. Shadow Pokémon can sometimes be overwhelmed by their emotions, indicating the relative instability of their Shadow state, and will sometimes enter either Reverse Mode or Hyper Mode. This state will be triggered more often the closer the Pokémon is to purification, making them generally more difficult to battle with until they are ultimately purified. In either state, it will refuse to accept any items from its Trainer. A Pokémon in this state can be cured of it by calling to it in battle or use of a scent, as well as several other methods, or can recover on its own.

An interesting quirk about Shadow Pokémon is their inability to be differentiated from normal Pokémon by all but those with certain abilities or tools. Shadow Pokémon emit a normally invisible dark aura that normal Pokémon do not, which so far has only been able to be detected by Rui through an innate ability, and Michael with his Aura Reader. The only exception is Shadow Lugia, which takes on noticeable alterations, namely having jagged silver eyefins and possessing an overall darker complexion.

Shadow Pokémon cannot level up, and any experience they gain in battle will be held until they are purified, at which point it will be awarded en masse.

Reverse Mode
When a Shadow Pokémon is in Reverse Mode, it still retains its loyalty to its Trainer, for the most part. It may refuse to use non-Shadow-type moves, but will have no issues when using Shadow-type moves.

Hyper Mode
Hyper Mode is much more dangerous than Reverse Mode, as the Shadow Pokémon temporarily loses its loyalty to its Trainer. It will not hesitate to attack Trainers in this state, unlike Reverse Mode.

When it is commanded to use a non-Shadow-type move, it may obey, or do one of the following:
 * Use a different move, usually one of its Shadow-type moves.
 * In a Double or Triple Battle, it may attack its teammate(s).
 * It may attempt to use its held item, if it has any.
 * It may do nothing at all.
 * It may return to its Poké Ball, even if it's under the effects of a trapping move such as Block.

Purification
Main article: Purification

A Shadow Pokémon's purification process will begin as soon as it has been snagged, which is directly indicated by its Heart Gauge. Replacing the experience bar, the Heart Gauge monitors how close the Pokémon is to being fully purified, with the dark purple fill gradually depleting.

Shadow Pokémon can be purified in various ways, each with varying levels of effectiveness:
 * Traveling with its Trainer: When a Shadow Pokémon is under the proper care of its Trainer, its heart will start to open, albeit very slowly.
 * Battling: When a Shadow Pokémon is sent into battle, its heart will open up a bit. Battling is also one of few ways Shadow Pokémon can enter Reverse or Hyper Mode.
 * Massaging: Using special scents, Shadow Pokémon can be massaged to open their heart.
 * Purify Chamber: The Purify Chamber, developed by the Pokémon HQ Lab between the events of Colosseum and XD, can quickly purify Shadow Pokémon through interaction with normal Pokémon.