The start of Pokémon Legends: Arceus is unlike any the mainline series has seen before: the protagonist falls from the sky and lands in the middle of the Hisui region. Other Pokémon games have the player start in a room of some sort - or a moving truck in the Hoenn games - with information about the world of Pokémon relayed to them by a professor or other important figure. One of the many ways Legends: Arceus deviates from the Pokémon series norm is by having the protagonist thrown quite literally into the action by having them fall from the sky.
[Warning - spoilers for Pokémon Legends: Arceus follow.]
The reason the protagonist in Pokémon Legends: Arceus falls from the sky is actually heavily tied to the game’s story, so the following information contains major spoilers. Even Pokémon Legends: Arceus’ post-game story that continues after the credits roll is a continuation of the game’s primary narrative, and involves the protagonist and their unique circumstances of arriving to Hisui. The reason the protagonist falls from the sky turns out to be a highly relevant piece of game lore.
When first arriving in Hisui, the people of Jubilife Village are highly suspicious of the protagonist. Professor Laventon, however, is grateful to have the protagonist help with capturing dangerous wild Pokémon and filling out the Pokédex. All the while, the protagonist gets to earn the trust of the people of Jubilife Village. The primary conflict in Pokémon Legends: Arceus grows to center around the expanding distortion in spacetime that appears above Mt. Coronet. As the game draws to a close, it turns out the balance between space and time is askew due to mysterious rising tensions between Legends: Arceus’ legendary Pokémon Dialga and Palkia. It’s up to the player, whose skills at capturing and battling with Pokémon compared to the average person proved indispensable over the course of the game, to capture both Dialga and Palkia to restore balance to spacetime. But as it turns out, it wasn’t just by coincidence that the protagonist had what it took to put a stop to Dialga and Palkia.
Before Falling From The Sky, Legends: Arceus' Protagonist Was In Sinnoh
There is evidence to suggest that the protagonist of Pokémon Legends: Arceus and the protagonist of Diamond, Pearl, Platinum, and their remakes, Brilliant Diamond and Shining Pearl, are one and the same. Although most protagonists in the mainline Pokémon games are aged 11 to 14, the protagonist of Pokémon Legends: Arceus is explicitly stated to be the oldest, with Professor Laventon remarking they appear to be around 15 years old. Considering the protagonist looks identical to the protagonists of the Sinnoh games - albeit older - it’s likely that they are the same characters a few years after the games set in Sinnoh draw to a close.
An unused room also exists in the files of Legends: Arceus that further solidifies this theory: the room is clearly modeled after the player’s room in the various Sinnoh games. The TV, game console (a Wii in the original games, and a Switch in the remakes and Pokémon Legends: Arceus hidden room), desk with laptop, certificate on the wall, window, rug, and bed are all in the same place. The floorboards and wallpaper also match those found in the Sinnoh protagonist’s room. There are some added details, such as a photo frame on the windowsill, to match the increase in environmental detail in Legends: Arceus, but it’s clearly meant to be the same room.
At the very start of Legends: Arceus, Arceus communicates to the player, telling them to meet every Pokémon. Then Arceus sends them to Hisui, and they promptly fall from the spacetime rift in the sky. If the protagonist is the same as the Sinnoh games’ protagonists, that would explain their proficiency with Pokémon battling and catching: by the end of the Sinnoh games, the protagonist has captured at least some Pokémon for their team, and has defeated Pokémon’s powerful Champion Cynthia to earn her title. The protagonist has also stopped Team Galactic from unraveling the seams of spacetime, and this experience is likely why Arceus chooses to send them back in time to Hisui.
The Legends: Arceus Protagonist Was Sent Back In Time To Stop Volo
The story of Legends: Arceus continues even after the player captures Dialga and Palkia. Together with hints from Cogita and help from Volo, the player can seek out all the Plate items. Plate items are associated with Arceus, as they can be used to change its type. Similar to the original Diamond and Pearl games, the Plates in Legends: Arceus have engravings on the back that reference the ancient lore of the creation of the universe. Obtaining these Plates in Pokémon Legends: Arceus is said to be key to meeting Arceus itself, so Volo insists the player finds them all.
It turns out Volo intended to take the plates from the protagonist so he could meet - and capture - Arceus himself. His interference to try and draw out Giratina - and, subsequently, Arceus, as Giratina’s own desire is to fight against Arceus - is what caused Dialga and Palkia’s discomfort and the expansion of the rift in spacetime. Volo’s motives seem a lot more well-intentioned yet misguided compared to Cyrus, as Volo wants to recreate the universe with no needless suffering, but they still share similarities in their ultimate goals and methods of achieving them. The protagonist from the Sinnoh Pokémon games, having already stopped Cyrus - descendant of Pokémon Legends: Arceus’ Cyllene - in a similar plot, would be a great person to enlist to try and stop Volo.
Without the protagonist, the people of Jubilife Village, who are still unaccustomed to Pokémon, would have stood no chance against Volo had he obtained all the Plates and drawn out both Giratina and Arceus. He is even given the title of “Pokémon Wielder” due to his incredibly powerful team of Pokémon partners, almost exactly matching Cynthia’s own team from the Sinnoh games. But the protagonist of the Sinnoh games, having already defeated Cyrus and Cynthia, would have the skills to team up with plenty of Pokémon and train them to be able to stop Volo. Their skills would also come in handy when searching for the Plates, since they can safely explore the vast Hisui region even with all of Pokémon Legends: Arceus’ dangerous wild Pokémon. They would also find the Plates when searching for every Pokémon like Arceus requested, because the Plates were in the possession of various strong Pokémon. Arceus made a wise choice in sending the protagonist into Hisui to nip Volo’s schemes in the bud.