Pokémon Mystery Dungeon: Gates to Infinity (Nintendo Cinematic Universe)

Pokémon Mystery Dungeon: Gates to Infinity is a Japanese anime film.

Summary
Pokémon Paradise become infected by the Bittercold.

Plot Elements

 * A boy has a weird dream and wakes as a Pokémon. Upon arrival, the Pokémon meets a partner Pokémon, who intends to construct a "Pokémon Paradise" near a settlement called Post Town. In the process of doing so, they befriend several Pokémon, including Dunsparce, Emolga, Virizion, Umbreon and Espeon.
 * Later on, the Pokémon meets Hydreigon who had featured in the player's dreams. Initially believed to be a villain, Hydreigon reveals himself to be the physical embodiment of the Voice of Life, who brought the player and other humans into the Pokémon world to save it.
 * Kyurem eventually confronts the Pokémon, the partner Pokémon and Hydreigon, who destroys Hydreigon and severely wounds the player to stop them from destroying the Bittercold – a presence created by the growing negative emotions of Pokémon which threatens to destroy the world, as he did with other human-turned Pokémon.
 * Some time later, the group returns to rescue Keldeo who was held captive by Kyurem, and defeats Kyurem and the Bittercold with the support from the Pokémon in Post Town and Paradise.
 * Hydreigon is reconstituted shortly afterwards, and the group celebrates their victory. However, the Pokémon is forced to return and vanish from the Pokémon world, to the strong grief of others.