It is curious! It seems like Johto and Kanto are somewhat isolated, but clearly it wasn't always that way, or the variants wouldn't be here to begin with...

[Lilith is no conspiracy theorist-- Or so she'd say, but the truth is she got roped along in enough of her sister's childhood investigations that it'd be easy for her to come up with some ideas as to why this is. However, she's also someone who values manners, and she realizes now she's forgotten hers so far.]

Excuse me, of course... My name is Lilith Clawthorne.