Pokemon Legends: Arceussets a unique prescident by taking place in the Hisui Region, which would eventually be called the Sinnoh Region many years later. A lot can change in the region depending on how much time has passed, and judging by appearances, alotof time will pass between the events ofPokemon Legends: ArceusandPokemon DiamondandPokemon Pearl. So much time will likely pass that the wildlife of the region could shift drastically, and Pokemon that may be staples inDiamondandPearlmay be absent fromPokemon Legends: Arceus, and vica versa.
In total, the Generation 4 Pokedexas ofPokemon Platinumfeatured 210 Pokemon, which does not include several Mythical Pokemon like Shaymin and Phione. It’s unclear how many Pokemon will be featured inPokemon Legends: Arceus, but with the introduction of Hisuian Forms and new evolutions, the roster ofPokemon Legends: Arceushas the potential to be even larger than that ofPokemon Diamond, Pearl, andPlatinum. At the time of writing, 121 Pokemon found in the Sinnoh Pokedex have yet to make an appearance in any trailers or screenshots fromPokemon Legends: Arceus.

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Every Gen 4 Pokemon Missing from Trailers and Screenshots
Here is every Pokemon from the Gen 4 Pokedex that has yet to be shown physically in all of the pre-release footage and screenshots so far.
This is the full list of Generation 4 Pokemon that are absent from the few trailers and screenshots present forPokemon Legends: Arceusso far, as of the September 2021 trailer thatintroduced Noble Pokemonamong other things. Now this isn’t to say that these Pokemon will be missing from the final release of the game. In fact, several Pokemon on this list are likely going to appear due to other Pokemon in their evolutionary line making an appearance.

Pokemon Whose Evolutionary Lines Are Completely Missing
These Pokemon have had no mention of them whatsoever in the trailers, whether it be the Pokemon themselves, or a Pokemon in its evolutionary line. In total, this list features 65 Pokemon who could potentially be missing fromPokemon Legends: Arceus.
A large chunk of these Pokemon are Legendary and Mythical Pokemon, which could honestly go either way in terms of their appearnace inPokemon Legends: Arceus. While the titular Arceus will be making an appearance in some shape or form, the others are still up in the air.
With the brief glimpes shown of the map inPokemon Legends: Arceus, the iconic lakes fromPokemon DiamondandPearlare still present, which means that Uxie, Azelf, and Mesprit could make an apperance. Whether they are catchable or not is a whole other question entirely. Arceus itself would bepeculiar and lore-breaking if players could catch it in-game, but Game Freak may have some special explanation up their sleeve for this.
The issue of whether Dialga, Palkia, and Giratina will make an apperance or not is definitely a curious one to say the least. InDiamondandPearl, Team Galactic sought to use these primordial entities to reshape the universe, but the player will be a part of the Galaxy Team’s Survey Corp, meaning the focus may not be reshaping the world just yet. However, it would be no surprise if Game Freak were to try totie the plot ofPokemon Legends: ArceustoPokemon DiamondandPearlin some way, consideringLegendsis a prequel.
As for the Mythical Pokemon, it’s truly hard to say if these Pokemon will appear or not. It would be great to see these often underrepresented Pokemon have some time to shine canonically, without being tied to a limited-time event. WhileBrilliant DiamondandShining Pearlreceive a Manaphy egg as a pre-order bonus, no such Mythical tie-ins have been announced forPokemon Legends: Arceusas of yet. Legitimate versions of Darkrai, Shaymin, and the other Mythical Pokemon introduced in Generation 4 are hard to come by, so perhapsPokemon Legends: Arceuswill give players an avenue to obtain these rare and difficult-to-obtain Pokemon.
Generally speaking, it seems that the vast majority of Pokemon from Generation 4 are present currently, including some new faces like Hisuian Braviary andeven new evolutionslike Basculegion. While some Pokemon may be a safe assumption (like the Gastly line being in the game because it is the counterpart to the Abra and Machop lines), there’s no real way of knowing for sure until Game Freak showcases more Pokemon that are appearing inPokemon Legends: Arceus. Hopefully more beloved Sinnoh Pokemon make their return as players venture back in time to the founding of the Sinnoh region.
Pokemon Legends: Arceusreleases on the Nintendo Switch on January 28.
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