A variety of new Pokmon and variant forms were introduced in Pokmon Legends: Arceus. Some of the Pokmon are evolutions of existing ones, such as Ursaluna evolving from Ursaring. Teddiursa and Ursaring, however, don’t have a new Hisuian form, but there’s still a new Pokmon in the evolution line. Other Pokmon have Hisuian evolutions rather than completely new forms, like the three starters in Pokmon Legends: Arceus. Different forms of Pokmon started with the Alola versions and Pokmon Legends: Arceus introduced Hisuian forms. Unlike Shiny Pokmon, different forms usually change more than the color scheme.

https://screenrant.com/pokemon-legends-arceus-hisuian-forms-regional-variants-list/