Shadow Pokémon are Pokémon whose hearts were corrupted and locked behind several "doors" keeping the light from their heart from shining through. Constant care and battle are needed to unlock the doors to the Pokémon's heart. After all the doors are unlocked the player can then purify the Pokémon using the Relic Stone in Agate Village or the Purification Chamber in the Pokémon HQ Lab.

Creation

Cipher created each Shadow Pokémon from his lab located close to the center of the Orre region. In the lab, Ein tried to perfect the formula for a Pokémon that was not afraid to attack other trainers. Once he found out that each Pokémon's heart could be locked away, he used this to create the Shadow Pokémon, perfecting his formula. However, due to the amount of corruption flowing from the Pokémon, it is possible to tell the difference between a normal "Pure" Pokémon and a "Shadow Pokémon". Only certain eyes can catch the strange, dark aura coming from them.

The Strongest Shadow Pokémon

The "strongest" Shadow Pokémon is usually considered to be Shadow Lugia, given the code name XD001. Lugia, already being the strongest Pokémon ever captured by Cipher, it was turned into a Shadow Pokémon and was said to not be able to be purified. But by having the Purification Chamber at high power, Michael was able the purify the Pokémon.

List of Shadow Pokémon

Colosseum
Bayleef	Croconaw	Quilava	Makuhita	Misdreavus	Slugma
Noctowl	Flaaffy	Skiploom	Quagsire	Furret	Yanma
Remoraid	Mantine	Qwilfish	Dunsparce	Meditite	Swablu
Sudowoodo	Hitmontop	Entei	Ledian	Suicune	Gligar
Piloswine	Sneasel	Stantler	Ariados	Aipom	Murkrow
Forretress	Granbull	Vibrava	Raikou	Sunflora	Delibird
Heracross	Skarmory	Miltank	Absol	Houndoom	Tropius
Metagross	Tyranitar	Smeargle	Ursaring	Togetic	Shuckle

XD: Gale of Darkness
Teddiursa	Ledyba	Poochyena	Houndour	Spheal	Baltoy
Mareep	Gulpin	Seedot	Spinarak	Numel	Carvanha
Shroomish	Delcatty	Voltorb	Vulpix	Makuhita	Duskull
Ralts	Mawile	Snorunt	Pineco	Swinub	Spearow
Grimer	Seel	Lunatone	Zangoose	Nosepass	Togepi
Paras	Growlithe	Shellder	Pidgeotto	Beedrill	Butterfree
Magneton	Weepinbell	Venomoth	Arbok	Roselia	Meowth
Natu	Primeape	Hypno	Sableye	Golduck	Raticate
Dodrio	Farfetch'd	Altaria	Banette	Kangaskhan	Scyther
Chansey	Lickitung	Magmar	Pinsir	Hitmonchan	Hitmonlee
Solrock	Starmie	Rapidash	Magcargo	Tangela	Dugtrio
Swellow	Electabuzz	Snorlax	Manectric	Salamence	Marowak
Lapras	Moltres	Zapdos	Articuno	Lugia	Tauros
Exeggutor	Rhydon	Mr. Mime	Poliwrath	Dragonite

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