In Pokemon Legends: Arceus, players are traversing a region that has been visited in other Pokemon titles, but in a brand-new time period - well-before the events of Pokemon Diamond and Pearl. While most would expect the Pokedex to be of a similar size to that of Diamond and Pearl since it is the same region, the game features plenty of Pokemon that are not a part of the Gen 4 Sinnoh Pokedex - including some new Pokemon and new Hisuian Forms for players to discover, which actually put it ahead of Generation 4's Sinnoh Pokedex by a fair margin.