Yeah. I was expecting something more about the ancient civilization. But nope. Just some vague messages about alphabet pokémon.

[He scratches Chen's head.]

That they're... bizarrely similar to something ancient Egyptians used to believe in. I can't believe I never made the connection before but they're like if you combined Shut with Ba, aspects of a person's shadow and personality. Their masks are definitely a form of death mask. Each one had a slightly different mask from each other. So... it seems like what the pokedex claims may have an air of truth to it.