Gladion's Silvally (Lightsoul)

Gladion's Silvally is a Legendary Pokémon he obtained in Alola.

Prior to Lightsoul: Sun & Moon
Silvally was a Pokémon created to fight Ultra Beasts. Four years ago, Silvally was created by an evil scientist of the Aether Foundation, Faba. During his research, Faba attempted to release an Ultra Beast into the Pokémon world in hopes of fulfilling Lusamine's dreams. However, a Nihilego emerged from the Ultra Wormhole and attacked Lillie. Faba and Gladion couldn't do anything but watch in horror until Silvally came and saved Lillie's life. Afterwards, Faba declared Silvally as a failure and placed restraints on it, which caused it to de-evolve into Type: Null. Its daring rescue as well as its appearance unintentionally caused Lillie to become fearful of touching Pokémon.

Lghtsoul: Sun & Moon
TBA

Personality
Silvally has the ability to sense the presence of Ultra Beasts and Ultra Wormholes. Silvally often becomes stressed when it senses danger, barking and lashing out when it feels threatened. As a Type: Null, its helmet was also a source of anxiety for it. Despite its anxiousness, it appears to trust its Trainer, and can be calmed down with Gladion's words. It eventually became able to trust Gladion enough to use the full extent of its power, breaking its restraints. It also has a strong connection to Lillie, having saved her from Nihilego during her childhood. It inadvertently caused Lillie's fear of Pokémon, and was ultimately what caused her to stop fearing them. For whatever reason, Gladion wants Silvally's existence to remain a secret.

After breaking its mask, it gained access to the RKS System.

Trivia

 * Prior to its evolution, Type: Null was the first Pokémon to be nicknamed as its evolved form, Silvally.
 * Unlike most other Pokémon in the anime, Silvally is not kept inside of a normal Poké Ball, instead being housed in an Premier Ball.