Mew and Arceus.

[PokeMangaObsessed]

Mew's D/P/Plt dex entry says that scientists think that it's the ancestor of all Pokemon since it can learn all TMs and HMs.

Arceus's D/P/Plt dex entry says that it created the world.
If you go to the Canalave Library, a book [indirectly] states that Arceus bore Dialga and Palkia, Mesprit, Azelf, and Uxie.

In the beginning, there was only
a churning turmoil of chaos.
At the heart of chaos, where all
things became one, appeared an Egg.
Having tumbled from the vortex, the
Egg gave rise to the Original One.
From itself, two beings the Original
One did make.
Time started to spin.
Space began to expand.
From itself again, three living things
the Original One did make.
The two beings wished, and from them,
matter came to be.
The three living things wished, and
from them, spirit came to be.
The world created, the Original One
took to unyielding sleep...

Therefore, Dialga and Palkia apparently started time and Space, and Mesprit, Azelf, and Uxie created spirit.
This would make Arceus the ancestor of all Pokemon.


You can't say that Mew may have created Arceus because:

In the beginning, there was only
a churning turmoil of chaos.
At the heart of chaos, where all
things became one, appeared an Egg.

Unless, I suppose, Mew somehow was that "churning turmoil of chaos" and later came into the form of a Pokemon.

Feel free to debate and state your own opinions.

 

[Hazri]

Wow, you'd be very sore giving birth to Palkia and Dialga.

 

[JoltIce]

I think that Arceus created Mew, and then Mew created all other Pokemon except for Dialga, Palkia, and the Lake Trio. Arceus also imbused Mew with the DNA of him and the Pokemon he created.

 

[Åzurε]

To me, it seems generally accepted that Arceus was first, and created Mew, from which all non-major-legendary pokemon came. Sometimes, even some of those.

 

[Niprop]

Arceus created the two trios, and then Mew (though Arceus was nice enough to give Mew his DNA, so he wasn't incomplete), which in turn created all the pokémon from Probopasses to Mr. Mimes. Then some time later Porygon and Voltorb came into the picture, leaving people to question whether the aformed two and their evolutions should be considered true pokémon. (Castform is also considered man-made, but unlike the others, Castform is related to and able breed with non-artificial pokémon.)

 

[Saltare.]

I would say Mew is the creator of Pokemon and such just because it came before Arceus. But now that I've put the pieces together, it's Arceus.

 

[Wh1teW01f]

Maybe Arceus was Mew's parent.

Or maybe Mew and Arceus came out of the same egg which would make them siblings.

 

[Feathing]

After Gen. 4th, I though Mew was the ancestor of all pokemon. I believed that Mew was part of the initial chaos.
Now, with Arceus in the spotlight, I believe that Arceus came from the egg in the chaos, creating then the trios and other pokemon. But which seems more 'realistic' (if something of this can be realistic) is that Mew born when Arceus created the other Pokemon.
Think about it, Arceus have must used lots of energy and power to create such a powerful pokemon as palkia and dialga. In that process, Mew appeared like a "leftover".
Being the first pokemon created, mew was the pokemon who received more powers from arceus, so he was created with the dna of all following pokemon.

Other theory can be, as Wh1teWo1f said, that Mew and Arceus were both born from the egg, but he didn't participate in the creation process, 'cause Arceus was created with more abilities to do that. So, arceus created Palkia, Dialga and Giratina, then the lake trio, then the Hoenn trio. The other legendaries, along with the non-legendaries, were appearing with time.
Which appears really intriguing to me is Celebi and Jirachi. They're like mew, but with different powers. I think they were born from an unique egg, and arceus gave them unique powers, almost equaling mew.

 

[Rich Boy Rob]

I'd say Arceus created the Universe and all the deities that control time and space and weather etc, then after creating the Lake Trio, he created mew to populate the Earth (or perhaps universe?). Mew then evolved (Darwin style) into all modern Pokémon except the Super Ancient/Powerful creation legendaries, Mewtwo and the Porygons.

 

[Allure XI]

Unless, I suppose, Mew somehow was that "churning turmoil of chaos" and later came into the form of a Pokemon.

This is what I personally believe -- that all of the leftover energy from the chaos that created Arceus eventually calmed down, and over many years, developed into what we know as Mew. This would make the fact that Mew shares the DNA of all Pokemon consistant, as Mew would share DNA with Arceus -- who shares DNA with the Pokemon he created.

I wouldn't say that Arceus is a descendant of Mew, or vice versa. Rather, they were born from the same beginnings. I don't believe that Arceus was aware of Mew's existence when he created the other Pokemon, nor did Mew create any Pokemon.