Pokémon Legends: ARCEUS
Okay, so new game, new theories and claims.
Basically I just wanna say all this stuff so when it comes out I can see how close I was....
Anyway, Sinnoh is the land of Time and Space, the main protagonists in Legends look exactly like Dawn/Lucas, and Arceus plays a major role in the story.
So my main idea is that an alternate version of Dawn/Lucas exists. (This is canon. There are multiple versions of them, as seen in Platinum and Masters). That alternate version then travels across space and time to end up in the Sinnoh region during Legends.
This "alternate" version of them never got a Starter Pokémon in the present-day Sinnoh, and that is why in Legends they have to choose another Starter.
They get brought to the past in another reality either because there is something wrong and they are the only ones who can fix it, or by mistake. Either way, Arceus comes into play by appearing and trying to have the player journey around in an attempt to fix the issue and return back to their own time.
Maybe there is an evil Team and they use Greninjas (which could be why Oshawott/Samurott is offered as a Starter instead).
That's as much as I can think of right now. Maybe I'll add more parts as I remember them, but this is the basic idea of my theories:
Alternate Dawn/Lucas go back in time to help Sinnoh.
Or the protagonists could just be Dawn/Lucas's grandparents.
I don't like that idea as much but....
