There are many myths in the Sinnoh region. Below are several from Pokémon Diamond and Pearl from the library in Canalave City:

Sinnoh Myth

Betray not your anger, lest ??? will
come.
Weep not with sorrow, or ??? will
draw near.
When joy and enjoyment come natural
as the very air, that is happiness.
Let such be blessed by the hand
of Master ???.
Those words were spoken often
as customary.

Notes

• It is generally suspected the ??? refers to Mesprit.

Sinnoh Region’s Mythology

Long ago, when Sinnoh had just been
made, Pokémon and humans led
separate lives.
That is not to say they did not help
each other. No, indeed they did.
They supplied each other with goods,
and supported each other.
A Pokémon proposed to the others
to always be ready to help humans.
It asked that Pokémon be ready to
appear before humans always.
Thus, to this day, Pokémon appear
to us if we venture into tall grass.

Notes

• This is an explanation why wild Pokémon appear in grass.

Sinnoh’s Myth

Three Pokémon there were.
Into the lakes they dove.
Deep, deep, drawing no breath.
Deeper, deeper they dove.
Into suffocating depths they dove.
Deeper, then deepest they alight.
From the lake floor they rise.
Bearing with them the power to make
vast lands, they rise again.

Veilstone’s Myth

A young man, callow and foolish in
innocence, came to own a sword.
With it, he smote Pokémon, which gave
sustenance, with carefree abandon.
Those not taken as food, he
discarded, with no afterthought.
The following year, no Pokémon
appeared. Larders grew bare.
The young man, seeking the missing
Pokémon, journeyed afar.
Long did he search. And far and wide,
too, until one he did find.
Asked he, "Why do you hide?"
To which the Pokémon replied...
"If you bear your sword to bring
harm upon us, with claws and
fangs, we will exact a toll.
"From your kind we will take our
toll, for it must be done.
"Done it must be to guard ourselves
and for it, I apologize."
To the skies, the young man shouted
his dismay.
"In having found the sword, I have
lost so much.
"Gorged with power, I grew blind
to Pokémon being alive.
"I will never fall savage again.
This sword I denounce and forsake.
"I plead for forgiveness,
for I was but a fool."
So saying, the young man hurled the
sword to the ground, snapping it.
Seeing this, the Pokémon disappeared
to a place beyond seeing...

Notes

• The Pokémon may possibly refer to Giratina.
• This proves that Pokémon are or were indeed eaten.

The Original Story

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...

Notes

• This has some parallels with Taoism and perhaps Shintoism. Creation in Taoism starts with a single energy, dividing into a duality (often referred to as Yin and Yang), then into three parts, and finally into the rest of creation. Compare, for example, the Korean Taeguk and Samtaeguk symbols, also seen in China and Japan which reflect this belief.
  • Similar parallels can be found in other creation myths, but not as directly. In fact, this seems to be more easily attributed to a common theme among creation myths than as a source of inspiration; several creation myths start with one being which splits or creates other beings from its body, including Hinduism and Greek mythology.

This myth describes how Sinnoh's first Pokemon, Arceus, also known as the Original One, came to be, from the Egg that appeared in the chaos. Also, the two beings that Arceus makes are Dialga and Palkia, creators of time and space, respectively. Arceus creates three living things as well, wihich are Uxie, Azelf, and Mesprit, the only Pokemon which can control Dialga and Palkia. Arceus thereafter went into the Hall of Origin high above the Spear Pillar, to wait for the Azure Flute to be played.

• This myth describes how the Pokémon world was created.

A Horrific Myth

Look not into the Pokémon’s eyes.
In but an instant, you’ll have no
recollection of who you are.
Return home, but how?
When there is nothing to remember?
Dare not touch the Pokémon’s body.
In but three short days, all emotions
will drain away.
Above all, above all, harm not
the Pokémon.
In a scant five days, the offender
will grow immobile in entirety.

Notes

• The effects caused by encountering the Pokémon can be described as the loss of knowledge, emotions and will.
• This refers to Uxie, Mesprit, and Azelf.
• The first part refers to Uxie's closed eyes and how if opened they would erase memory.

Sinnoh Folk Tales

"Sinnoh Folk Story 1"
Pick clean the bones of Pokémon
caught in the sea or stream.
Thank them for the meals they
provide, and pick their bones clean.
When the bones are as clean as can
be, set them free in the water from
which they came.
The Pokémon will return, fully
fleshed, and it begins anew.

"Sinnoh Folk Story 2"
There lived a Pokémon in a forest.
In the forest, the Pokémon shed its
hide to sleep as a human.
Awakened, the human dons the
Pokémon hide to roam villages.

"Sinnoh Folk Story 3"
There once were Pokémon that
became very close to humans.
There once were humans and Pokémon
that ate together at the same table.
It was a time when there existed no
differences to distinguish the two.

Notes

• In the literal translation of Sinnoh Folk Story 3, the myth originally referred to Pokémon and people marrying each other.

The Snowpoint Temple Myth

A body of rock.
A body of ice.
A body of steel.
When gather those three together,
the king will appear.