This is my first time writing a Pirate AU as well, so sorry for some mistakes and all, besides it's only a one shot, so it's short.

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Aye matey! Ever heard of a story called 'The Tale of Two Captains'?

Well, glad ya don't!

It's a tale of two ships with their own captains.

The Mystery Shack; a fierce, fearless yet kind one, might I say. Those pirates always get fools gold! Fighting skills are their expertise! They always fight this mysterious monsters they encountered, moreover they came back with filthy gold! Rich bags I say! And all thanks to their captain: Captain Mason "Dipper" Pines. An 18 year old brown haired pirate. Has a twin sister named Mabel Pines, his first mate. He's the most fearless one on his ship. Never gave mercy. But, secretly a kind and sweet one, only to his favorite crew..

He and his twin are trained as pirates since birth, yes. Trained by their Great uncles; Stanford and Stanley Pines. They stopped 'pirate-ing' because of age, as the former captain of The Mystery Shack, Former Captain Stanford Pines, passed it to his great nephew, saying not to repeat his mistakes. Their parents passed away at such a young age, so their 'Grunkles' took care of 'em.

And this other ship named, The Mindscape. There are the most feared ones among pirates ever witnessed or encountered. See, they are not humans, but demon pirates.

All of 'em are deceiving, using their piffy powers and magic just to get what they wanted. Fools gold as well, easily gets it in a snap of their fingers. But no, the fingers of their fierce and merciless captain: Captain Bill Cipher.

A dream demon, the powerful one of all kinds! Along with his twin brother, William Cipher, a little kitten and too kind for his own good, unlike his brother. Bill Cipher is the most deceiving of 'em all, a ruthless captain that shows no mercy to any kind! Even through his twin, but there's this 'sibling moments' going on to 'em. He has anger issues that he had to kill someone off his ship, he's immediately irritated, so don't mess with Cipher if you don't want to be put in death. He was feared, he loves power, power over others who are scared of him.

But, one is not, and that is...

Captain Dipper Pines..

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Sea gulls chased each other through the wind, chasing above of a huge pirate ship which is named 'The Mystery Shack'. Its captain, Captain Mason Pines who goes by the name 'Dipper' stirred the steering wheel with a small smile creeping up his face. His loose brown hair waves from the wind as the white feather of his blue tricorn hat covers his chestnut messy hair.

The roaring waves of the ocean barely reaches the main deck of the ship, as the crew finishes their chores: tidying up chambers, except for Captain Dipper's since the brunet captain doesn't want anyone in his office and sleeping quarters, untying ropes and tying it again to tighten more, cleaning the wet deck, and other things.

The ocean's wave proudly reached the deck as the crew laughed at each other for getting wet. Dipper who saw it chuckles under his breathe, yelping when his first mate, his twin sister Mabel Pines startled him.

"HEYA BRO BRO!!" yells her. Dipper grips the stirring wheel and his chest tight, a surprised look taking over his once calm face.

Mabel giggles, brushing her long hair away from her face. The two of them are born twins, like mentioned before, the best part is, Mabel is older from Dipper by 5 minutes, and still the youngest took over the ship.

The former captain of the Mystery Shack, Stanford Pines, passed the ship to his intelligent great nephew, Dipper. Both of the captain and former captain knew about the supernatural, mythical creatures lurked both land and the depths of the ocean.

Dipper breathes in, calming himself down, he looked at his grinning twin, "DON'T SCARE ME LIKE THAT, MABEL!"

Said older twin laughs, clutching her stomach tight. Her suitable pink pirate dress reaches her knees, bouncing when she hysterically laughs.

"Sorry!" she apologizes, suppressing her giggles.

"Captain!" someone yells, as Dipper snap his head towards the direction of the voice. He looked to see the most feared pirate ship to all the Seven Seas: The Mindscape.

That ship is filled with demon pirates, with the most powerful dream demon of all: Bill Cipher.

The demon filled ship appears from no where from here and there. Dipper never met its captain, he smirks when the crew of The Mindscape attacks.

"Prepare your weapons, scallywags!!" he yells to his own crew, glancing at his first mate who got the signal. The brunet took out his sword, grabbing a rope nearby and swinging down to the center of the deck.

Demon pirates swarm the Mystery Shack's main deck, as the skillful crews of the ship attacks them. Yells were overheard between those ships, clashing of swords joined in, its metal clanking rang through.

Dipper thrusts his sword between his twin's attacker, and managed to caught the demon off guard. Mabel then immediately jabbed her sword to her attacker's stomach, as it slowly dissipated into air. She nods at her brother who smiles at her, now parting their ways. Dipper found the captain of The Mindscape.

The blonde captain fought off his crew's preys. A woman with platinum (fake) blonde hair is his target. He smirks, teleporting behind the woman who was fighting off one of his crew, Pyronica.

He then sidestepped, impaling his golden sword to the other blonde who choked out blood. He grins, high five-ing Pyronica. He turns to see his first mate, his twin brother Will, fighting off The Mystery Shack's first mate.

Geez, when did Will became a pro? the blonde asks himself while chuckling as he saw his twin fights off the brunette pirate skillfully, thrusting his sword behind him when he senses someone was about to 'attack' him. Bill then skips off, happily killing other human pirates on the ship.

Meanwhile, Captain Dipper already murdered 4 demons off, now filled with his own sweat and demon blood. The demons he killed disintegrated into air, leaving red ashes as their demon blood. He's now fighting beside his sister, after helping her with a blue haired demon that he assumes as the invaders' first mate. The demon automatically vanishes when Dipper was about to strike him, as the brunet man cusses under his breathe.

His sword with blue handle is filled with magic that can fight mythical creatures off, well all except for very powerful ones, it can only injure them. His Grunkle Ford, the former captain of his ship, gave it to him, he even remembers his idol's last words before he aboard The Mystery Shack, not one of the crew, but as captain.

"Don't trust a demon, if you will,
If you do, it will kill.
If it gave mercy,
Then it's a sign as a great blessing."

Those rhythmic words made him baffled at first, but couple of years arrived, he understood. He scoffed, huffing a laugh, impaling another demon skillfully. Demons will never gave mercy! It's hard to believe that for every human being! He doubts that it will ever happen, even to the most powerful demons.

Mabel disappears behind him, giving him a feel of alert, he saw her appear 30 feet away as she was about to be attacked by one of the invaders, until her instincts came flashing as she fought it off. She gave him a thumbs up, telling him that she's okay, as the younger twin returned the gesture.

But things last.

His small smile faded when he heard a chuckle behind him. The Mindscape's Captain.

"Oh lookie here! The captain of this pathetic ship!" The blonde waves off a smirk, twirling his sword around.

Dipper faced him with a growl, a shadow casting over his eyes as he grip his sword tight.

"Never say that again demon!" he yells, charging at the blonde who already knew the brunet's strike.

Bill twirls away from him cockily, as if he's dancing. A dance with blood.

"You little-" Dipper stopped, aiming again as the duel began. Their swords clashing, metal ringing with the others.

Minutes past, both are drenched sweat, as well as others, but it seemed since the Captains' battle occurred, none of their crews died on that time, but with injuries.

"Give up, kid," Bill pants out, blocking a thrust from Dipper.

"Never," The brunet hisses out, double sweeping below, catching the blonde demon off guard as he's knock off and fell to the wooden deck of the ship. Dipper immediately stepped on the demon captain's chest, aiming his sword to the other's neck, panting heavily.

"Who's gonna give up now?" Dipper teases with a wide smirk. It softens and turns into a confused one when Bill says this;

"No one will, Pinetree."