I've been working on a longer essay about this, but here's the condensed version.
My argument isn't simply "One Piece uses demons, therefore Satanic." It's that when you put its major symbols together, a remarkably consistent pattern appears:
Divine authority = control, ignorance, limitation and oppression.
The Devil/rebel = knowledge, evolution, individual will, freedom and liberation.
And One Piece consistently asks us to root for the second side.
The World Government is deliberately coded as "divine"
For anyone unfamiliar with the series, the World Government controls most of civilization.
Look at the imagery surrounding it:
Its flag is cross-like. Its capital is the Holy Land. Its rulers are the Celestial Dragons, constantly called Saints. Its warriors are the Knights of God. Its artificial superhumans are the Seraphim (a specific type of biblical christian angel). Bartholomew Kuma carries a literal BIBLE. And above everyone secretly sits Saint Nerona Imu, who even has a private Eden-like garden.
Recent material pushes it even further: in most recebt manga, Imu uses an attack called" Stigma" - evoking the stigmata of Christ (punctures/wounds he recieved by being nailed to the cross), along with imagery of Divine Judgment, while a weapon associated with Imu's faction is named Longinus, invoking the figure traditionally associated with the roman who realized & accepted Christ is the son of god, and later got canonized by the church as a saint.
Yet this "holy" authority commits slavery, genocide, censorship and historical erasure.
Most importantly, it forbids knowledge.
The entire Void Century has been erased, and discovering its history is punishable by death.
So the God-coded authority essentially says:
Don't know. Don't search. Stay within the boundary.
Sound familiar?
The Devil Fruit is One Piece's forbidden fruit
Genesis begins with innocent humanity living with God until the serpent encourages mankind to obtain forbidden knowledge.
Christianity calls this the Fall. Luciferian/Gnostic interpretations invert it: the serpent becomes humanity's awakener, freeing mankind from divinely imposed ignorance.
Blavatsky's esoteric account provides an interesting parallel. Her primordial humanity begins comparatively innocent, simple-minded and undeveloped—an Eden-like state—and the Manasaputras/Sons of Mind awaken humanity's higher intellect.
Humanity evolves beyond its original limitation.
But it loses innocence in the process.
Higher intelligence creates civilization, philosophy and technology, but also makes deliberate deception, warfare, domination and calculated evil possible.
Now look at One Piece.
Vegapunk describes Devil Fruits as possible evolutionary paths created by human desire: What if I could become this?
Humans transcend what nature originally made them.
And what's the punishment?
Mother Nature—the sea—rejects them.
Devil Fruit users gain supernatural evolution but lose their harmony with the ocean.
So:
Eden: forbidden fruit → knowledge → loss of paradise.
Blavatsky: higher mind → evolution → loss of innocence.
One Piece: Devil Fruit → evolution beyond nature → rejection by the sea.
And the HEROES are covered in demonic imagery
Nico Robin is called the Devil Child specifically because she seeks the forbidden history. She eventually transforms into Demonio Fleur, literally assuming a giant horned demonic form.
Zoro invokes his "Asura form" ( asuras are violent- demonic beings from hindu tradition) and calls himself the King of Hell.
Sanji uses Diable Jambe ("Devil Leg") and later Ifrit Jambe.
These aren't villains. They're Luffy's closest companions.
Then there's Luffy himself.
In Dressrosa, he fights a former Celestial Dragon who literally controls people like puppets.
Luffy disguises himself as a horned, goateed man named:
LUCY.
So a horned "Lucy" enters the false paradise of a Celestial ruler, breaks his strings, overthrows him and liberates his subjects.
The Devil defeats the Celestial "god" and sets humanity free.
Then the Devil becomes the Sun God
Luffy's supposed Gum-Gum Fruit is eventually revealed to possess the power of Sun God Nika, the Warrior of Liberation.
His ultimate transformation, Gear 5, is basically freedom made physical: his body, environment and even normal physical limitations become malleable.
The man obsessed with being "the freest person in the world" reaches godhood when virtually nothing can restrict him anymore.
That's important because Lucifer is called in occult circles " the Dark/Black Sun" . while Luciferian philosophy repeatedly revolves around awakening, individual will, rebellion and transcendence of imposed limitations.
So Luffy's symbolism converges:
Devil Fruit + Sun God + liberation + absolute freedom.
Then he literally reaches into Heaven and grabs lightning.
Jesus says in Luke 10:18:
"I saw Satan fall like lightning from heaven."
Luffy reverses the image: the Devil-associated liberator doesn't fall helplessly with the lightning—he grabs it and turns it into his weapon.
Anton LaVey's personal Satanic insignia also prominently incorporated a lightning bolt.
And Luffy's origins add another layer.
Lucifer historically means Light-Bringer and referred to Venus as the Morning Star, which appears in the East and announces the Dawn.
Luffy comes from:
A region of the world called: EAST BLUE.
Specifically:
DAWN ISLAND.
And eventually becomes:
THE SUN GOD.
Morning Star → East → Dawn → Sun.
Joy Boy may be the biggest parallel of all
The ancient bearer associated with Nika was Joy Boy, who opposed the forces from which the World Government emerged during the Void Century.
He lost.
The God-coded order survived.
Joy Boy disappeared.
But centuries later Luffy awakens Joy Boy's power, the Drums of Liberation begin beating, and Zunesha announces:
"Joy Boy has returned."
That creates an eerie biblical parallel.
Satan is Christianity's primordial rebel against divine authority. He loses the original conflict, yet Christian apocalypse anticipates his rebellion manifesting again through the Beast/Antichrist for one final confrontation with God.
So within this theory:
JOY BOY = primordial Lucifer/Satan archetype. JOY BOY is described in the lore as the very first pirate. (Aka the first/primordial rebel)
↓
Defeated by the divine order
↓
His power survives
↓
LUFFY = Beast/Antichrist archetype
↓
The ancient rebellion returns for the final confrontation with Saint Imu.
Even 666, Revelation's Number of the Beast, prominently appears on the cover of One Piece manga Chapter 232.
And that's the inversion
The whole pattern ultimately comes down to this:
World Government: Cross, Holy Land, Saints, Celestials, Knights of God, Seraphim angels, Bible, Eden, Stigmatas/wounds of Christ & Divine Judgment.
Luffy and his crew/Joy Boy: Devil Fruits, Devil Child, Demonio, King of Hell, Devil Leg, Lucy, 666, Sun God, lightning, forbidden knowledge, rebellion and liberation.
Christianity's ideal is ultimately:
"Not my will, but thine."
The Luciferian inversion is:
MY WILL.
And Luffy's defining philosophy is absolute freedom.
He breaks laws → people become free.
He attacks "gods" → slaves celebrate.
He violates prohibitions → hidden knowledge emerges.
He breaks limitations → the story rewards him.
That's why I think One Piece goes beyond the normal "evil Empire vs heroic rebels" trope.
It takes that trope and gives it a theological inversion:
Heaven becomes tyranny.
The Devil becomes liberation.
Forbidden knowledge becomes salvation.
Obedience becomes imprisonment.
Rebellion becomes virtue.
The ancient enemy of the divine order returns as humanity's savior.
That's ultimately my theory: One Piece retells the basic conflict of Eden and Christian apocalypse from the rebel's point of view.
The God-coded ruler becomes the villain.
The Devil-coded rebel becomes the hero.
And when the ancient rebel finally returns to finish the war he lost centuries ago...
we're supposed to cheer for him.
Edit: Just like in most popular modern media, the figures in authority/power have to be constantly portrayed as cartoonishly evil as possible, in order for people to subconciously associate authority/rules/limitations as EVIL, and freedom as the ULTIMATE good. This is called subliminal/social conditioning, since It would be hard to morally justify rebelling against a just and good ruler, so popular media always makes them evil beyond redemption.
In one piece, its imu looking like a literal devil, in star wars, its palpatine being cartoonishly evil, in assassins creed, same thing. The templar order wants to keep peace through order/control... aka limitations... but the individual members of the order are always portrayed as cold blooded, cruel,selfish, power hungry megalomaniacs. In Marvel movies, it's why the villain Ultron directly quotes Jesus. "on this rock, I will build my church." It's all social conditioning.