>The Scarlet Book, which will appear in Pokémon Scarlet, and the Violet Book, which will appear in Pokémon Violet, are records from an expedition, and they were written long, long ago. The expedition is said to have traversed an uncharted area of the Paldea region, but whether or not the accounts depicted in the books are true remains unclear. It seems Arven always carries a copy of one of the books with him.
>Photographs and sketches of unidentified creatures fill the pages of the Scarlet Book and Violet Book. While there have been sightings of similar creatures in recent years, such reports are rare, and specific details of the creatures’ biology are still a mystery.
>The Monster Known as Great Tusk: The book describes how this savage monster attacked the expedition team with its large body and tusks, mortally wounding one of the explorers.
>The Monster Known as Iron Treads: It is said that when this monster curls its body and rolls to attack, it leaves a trail gouged into the ground, as if it had scorched the earth.
From the info Khu gave us we can infer the "paradox" pokémon from the Scarlet and Violet books are mythological creatures born from the imaginary of humankind that come to live in the wild rift at the center of the Paldea region. Now we had a first glimpse to the past and future themed versions of a mythological Donphan, what other mythological pokemon you want to see imagined into life? The ones waiting to be revealed are:
>Scalet Book: Volcarona, Amoonguss, Jigglypuff, Misdreavus, Magneton, Salamence and (as DLC) Suicune
>Violet Book: Volcarona, Gallade, Hariyama, Delibird, Zweilous, Tyranitar and (as DLC) Virizion