The Protagonist of the Story. Percy is but A Young boy with a Heart of Gold and a Silver Willed Soul, Percy is primarily the chosen target for the Emperor's Tarot. A once normal boy in the small town in Corneo, He was whisked into a world of wonderful sights and tragic fates. He is the main Protagonist of the story, Doing no acts of evil, and protecting all who he loves.

Trivia:

Despite Chronus Nocturne being made in 2022, on the 6th of November, His looks have been revealed prior to that point in time.

His name refers to Alverton Hills asylum, a map created in Fortnite creative. It then carried over to Percy as a character.

In his Pokémon form, the crown mark between his eyes is a reference to the Crown Symbol in the Kingdom Hearts franchise.
On the topic of the sigil, it is known as the Emperor's Sigil in this universe, and it is primarily connected to Garleon, Percy and a new character, Kahato Lyoko.

Percy is Partially inspired by Sora, the main Protagonist of Kingdom Hearts. His sister, Lorelei Alverton, could be comparable to Kairi, and his other friend, Keijo, Could be Comparable to Riku.

Percy and Jerry as a team refers to the Protagonist and his partner in the Animated Special: PMD: Explorers of Time and Darkness, and its sequel, Beyond Time and Darkness.
Their introduction is also derived from the same Special, but differently.

Originally, Percy lost his humanity in the fight against Antimatter. This has been retconned, into Percy retaining his humanity, But losing a particular ability much later.

Percy originally had a streak of Bad luck, which caused him trouble wherever he went.
This was retconned, but it was referenced in his bedroom, which shows a broken mirror.
This would imply that he has had bad luck prior to the events of the game, but not on a grandiose scale as he did before.