Pokémon Form Change

As the Pokémon games have progressed, many Pokémon have gained forms and in doing so, they need you to get a special item or go to a special location in order to be able to change the form which has changed from previous games. These list the ways to get specific Pokémon forms for the small amount of Pokémon with alternate forms within the games that slightly differ from normal or require specific locations

Rotom

Rotom's forms make a return once again, inexplicably through time. Ginter of the Ginko Guild has got a variety of special items he sells you and some will be mysterious Mechanical items he doesn't know what are used for. Buy them and they will go in your lodgings and allow for you to change Rotom's form at will
Mechanical Box - Heat Rotom
Mechanical Cabinet - Frost Rotom
Mechanical Tub - Wash Rotom
Mechanical Pinwheel - Fan Rotom
Mechanical Circular Saw - Mow Rotom

Rotom Mow Frost Heat Fan Wash
Rotom Mow Rotom Frost Rotom Heat Rotom Fan Rotom Wash Rotom
  Leaf Storm Blizzard Overheat Air Slash Hydro Pump
Base Stats:

HP: 50
Attack: 50
Defense: 77
Sp. Attack: 95
Sp. Defense: 77
Speed: 91
Base Stats:

HP: 50
Attack: 65
Defense: 107
Sp. Attack: 105
Sp. Defense: 107
Speed: 86
Rotom Room

Cherrim

As Sunny Day isn't a thing in this game, Cherrim's form is harder to get. It is still tied to the weather and only appears when it is Sunny. Cherrim has received an upgrade in this game. Due to the lack of abilities in the game, its stats have been increased in its Sunshine Form

Overcast Form Sunshine Forme
Overcast Form Sunshine Form
Grass Grass
Base Stats:

HP: 70
Attack: 60
Defense: 70
Sp. Attack: 87
Sp. Defense: 78
Speed: 85
Base Stats:

HP: 70
Attack: 90
Defense: 70
Sp. Attack: 87
Sp. Defense: 117
Speed: 85


Cherrim

Burmy

As with all games, Burmy changes its form based on location. As this game is set in the past, the locations vary depending on each of the biomes and change after battle: Plant Cloak - Jubilife Village, Obsidian Fieldlands
Sandy Cloak - Crimson Mirelands, Cobalt Coastlands
Trash Cloak - Coronet Highlands, Alabaster Icelands

Arceus

Arceus' forms have undergone a bit of a change. In this game, all Arceus' Plates are now key items. All you need to do is use the Plate on Arceus and it will change form. This includes the new plate, the Blank Plate, which changes Arceus back to its Normal-type

There is another plate, however. The Legend Plate is obtained when you get Arceus and can be used in an identical way. It will make Arceus its Normal-type, but with a twist. The move Judgment will automatically change type to a type that will be Super Effective on the opponent. When you use the move, it will change Arceus' type to this type as well.

The plate prioritises damage then resistance to the opponent Pokémon's types and picks the type based on that in the following priority:
4* Weakness, Immune to opponent
4* Weakness, 0.25* resistance to opponent
4* Weakness, 0.5* resistance to opponent
4* Weakness, standard damage from opponent
2* Weakness, Immune to opponent
2* Weakness, 0.25* resistance to opponent
2* Weakness, 0.5* resistance to opponent
2* Weakness, standard damage from opponent

Arceus - Legend Plate

Dialga

In this game, Dialga has received a new form, the Origin Forme. This form is the one you face in the game if you picked Irida to work with in the story. To change Dialga's forms, you need to get the Adamant Crystal from Adaman during the Request: The Diamond Clan's Treasure. Once obtained, simply use the item in the menu to change Dialga's forms at will

When in Origin Forme, Dialga's Roar of Time move increases in power to 140 Power but with a reduced accuracy of 75

Standard Form Origin Forme
Standard Forme Origin Forme
Steel Dragon Steel Dragon
Base Stats:

HP: 100
Attack: 120
Defense: 120
Sp. Attack: 150
Sp. Defense: 100
Speed: 90
Base Stats:

HP: 100
Attack: 100
Defense: 120
Sp. Attack: 150
Sp. Defense: 120
Speed: 90


Dialga Origin Forme

Palkia

In this game, Palkia has received a new form, the Origin Forme. This form is the one you face in the game if you picked Adaman to work with in the story. To change Palkia's forms, you need to get the Lustrous Globe from Irida during the Request: The Pearl Clan's Treasure. Once obtained, simply use the item in the menu to change Palkia's forms at will

When in Origin Forme, Palkia's Spacial Rend move decreases in power to 80 Power with a reduced accuracy of 85 but a higher chance of critical hits

Standard Form Origin Forme
Standard Forme Origin Forme
Water Dragon Water Dragon
Base Stats:

HP: 90
Attack: 120
Defense: 100
Sp. Attack: 150
Sp. Defense: 120
Speed: 100
Base Stats:

HP: 90
Attack: 100
Defense: 100
Sp. Attack: 150
Sp. Defense: 120
Speed: 120


Palkia - Origin Forme

Giratina

Giratina's forms make a return. In this game, you will catch Giratina already in its Origin Forme but immediately afterwards, you will get the Griseous Core item. Once obtained, simply use the item in the menu to change Giratina forms at will

When in Origin Forme, Giratina's Shadow Force move increases power to 120 but reduces accuracy to 80

Standard Form Origin Forme
Alterd Forme Origin Forme
Ghost Dragon Ghost Dragon
Base Stats:

HP: 150
Attack: 100
Defense: 120
Sp. Attack: 100
Sp. Defense: 120
Speed: 90
Base Stats:

HP: 150
Attack: 120
Defense: 100
Sp. Attack: 120
Sp. Defense: 100
Speed: 90


Giratina Origin Forme

Tornadus, Thundurus, Landorus & Enamorus

The Incarnate Pokémon from Unova have made an appearance in Hisui and, as with prior games, you can use the Reveal Glass in order to change their form from the item menu. The Reveal Glass is given after completion of the request Incarnate Forces of Hisui

Tornadus - Incarnate Forme Thundurus - Incarnate Forme Landorus - Incarnate Forme Enamorus - Incarnate Forme
Tornadus - Therian Forme Thundurus - Therian Forme Landorus - Therian Forme Enamorus - Therian Forme
Tornadus Thundurus Landorus Enamorus


Tornadus, Thundurus, Landorus & Enamorus

Shaymin

Shaymin's Sky Forme is also available in the game. During the request A Token of Gratitude, you will get given the Gracidea as a hint to find Shaymin. When you have Shaymin in Floaro Gardens, you can use the Gracidea on it in the item menu. It reverts when Shaymin is boxed and can't be used at night, though the form no longer reverts at night until you send it into battle

Land Forme Sky Forme
Land Forme Sky Forme
Grass GrassFlying
Base Stats:

HP: 100
Attack: 100
Defense: 100
Sp. Attack: 100
Sp. Defense: 100
Speed: 100
Base Stats:

HP: 100
Attack: 103
Defense: 75
Sp. Attack: 120
Sp. Defense: 75
Speed: 127


Shaymin Sky Forme