Some of you might have an issue with Enterprise and Bismarck being, like, the final boss of the story, facing off against Luffy, and piloting a giant robot to boot. Some of you might think that the Sirens, specifically Arbiter, should be the final antagonists instead.

First off, the reason I made this story is because I want to try something different with crossover formulas. In more or less every crossover, the protagonists of both series become friends with each other and work together to take down villains. Any conflict they have with each other happens early on in the story, only for misunderstandings to get resolved quickly and thus everyone becoming friends.

When writing stories, I like to try out different things that most people don't do, which made me think that it would be a great idea if a crossover exists where the protagonists of both series never got along with each other and are bitter enemies to the end.

One Piece has always been my favorite anime series, and around the time I was thinking of this kind of crossover, I became hooked to Azur Lane thanks to the 2019 anime. Considering that the protagonists of One Piece are technically lawbreakers, while the protagonists of Azur Lane are basically law enforcers, I figured that a crossover between these two series is exactly the thing I was looking for.

Therefore, I created this story with the mindset that the ship girls and the Straw Hats will NEVER get along with each other from beginning to end. They will remain enemies all the way to the end of the story, hence the final battle I prepared.

This may be different from the kinds of crossover formulas you're used to, and some might think that changes aren't necessarily a good thing. That is a subjective topic, but I still think it's worth a try coming up with this kind of crossover. Sometimes it's good to stand out and be different from everyone else!

Chapter 25
The Siren Empress


Being the fleet admiral, Sakazuki didn't leave New Marineford. He stayed in his office and was able to see what was happening at Delta Island using a Transponder Snail that can record live footages, brought there by the Marines.

Despite said snail being on one of the Marine ships out at sea, the appearance of the giant robot Enterprise and Bismarck and piloting could still be seen from that location.

"What in the world?!" said Sakazuki in shock when he saw the robot. Speaking into a different Transponder Snail, he asked, "What is with that giant thing?! What's going on there?!"

Vice Admiral Strawberry was on the other end, responding to him. "According to reports, it has something to do with the Azur Lane!"

"When are they able to do something like this?!" said Sakazuki. "They better not turn against us for whatever reason using that thing!"

"You probably don't have to worry about that, because according to more reports, not only are they currently in possession of the Eternal Pose leading to Laugh Tale, they are also engaged against some of the more notorious pirates, such as Straw Hat Luffy, Katakuri of the Big Mom Pirates, and even the revolutionist Sabo!"

"Is that so? That's good to hear," said Sakazuki. "Continuing pressing against the pirates! Make sure that none of them leave the island alive!"


Javelin, Laffey, Ayanami, and Z23 were looking up at the giant robot with looks of awe. "I didn't know Bismarck can do something like that…" said Z23 in disbelief. "Did she really get this from the golden Wisdom Cube?"

"I have the feeling that there is more to this than it seems…" said a worried Ayanami.

"But she should still be on our side, right?" said Javelin. "Surely she wouldn't become corrupted by power or something like that and attack us too, right?"

Suddenly, they heard the sounds of explosion, and they turned around to see the Siren ships launching attacks at the shore, not to mention fighting the Marine ships out at sea.

"We should be focusing on attention on that instead," said Laffey.

"Right," said Z23 with a nod. "We can't let the sight of that thing take away our attention. Let's go and show those Siren ships our power!"

"You bet I will!" shouted Shigure as she ran past them on all fours at a fast speed. The wolf-like ship girl ran across the water surface towards one of the Siren ships, which seems to have noticed her and began firing shots in her direction.

Shigure leaped high into the air and then slashed the air with her claws that are the result of her rigging's new transformation. Energy blades were fired at the ship, destroying some of the guns on it. Shigure landed onto the deck of the ship and then rushed towards the lookout tower.

New guns appeared on the deck and fired at her, but she ran at a swift speed and made several turns and jumps to avoid the shots. "You can't hit me! I'm too lucky to get hit!"

With an incredible leap, she jumped all the way to the top of the lookout tower, where a pitch black window is. Throwing a punch at the glass, she created a hole on it, and purple light poured of it. Looking through the glass, she could see a purple Wisdom Cube inside.

"Take this!" Taking aim with the guns on the back of her hand, she fired at the Wisdom Cube while jumping back into the air. The shots struck the cube and destroyed it.

A loud sound similar to that of an engine was emitted from the ship, and then it died down. All the guns on the ship stopped working, and any lights that were turned on darkened as well.

Explosions suddenly erupted from all over the ship, so Shigure hurriedly jumped off the deck and into the sea before she caught in it. The Siren ship was in flames in a matter of seconds and eventually sank.

"Haha! How'd you like that? Consider yourself unlucky running into me!" she said in triumph.

Not far away, some Marine ships were firing cannonballs at a Siren ship, but their attacks weren't going any good to it. The cannonballs caused harmless explosions when they struck the Siren ships and sometimes even bounced off them harmlessly.

The Siren ship, on the other hand, was inflicting major damage to the ships, putting holes on them and setting them on fire as well. The Marines on board were panicking and crying for help.

Just as the Siren ship was ready to fire at the ships again, putting them down for good, a giant white fox suddenly pounced onto it and roared loudly. Kaga was standing on top of the fox. The fox turned to the structure containing the Wisdom Cube and fired blue fireballs from its turrets at it.

The fireballs destroyed the lookout tower as well as the Wisdom Cube inside, and the Siren ship began sinking while exploding. The fox jumped off the destroyed ship and landed on the water surface, standing on it as if it was water. It also kicked some water onto the burning Marine ships to put out the fire. The Marine cheered for her and thanked her.

"Aim for the lookout towers! That's where the Wisdom Cubes powering them are!" Kaga told them.


Luffy and co. stared down at the giant robot, waiting for it to make a move. "Eat this!" shouted Bismarck, whose voice was so loud it could be heard in the distance as well. The various guns on the robot's body fired energy projectiles downwards, aiming for the pirates down below.

With swift movements, the pirates moved around nonstop to avoid the incoming projectiles as if they knew where they were going to hit, which is indeed true due to them using observation haki to predict their trajectories.

"I will not forgive anyone who dares lay a hand on my Luffy!" Hancock shouted as she ran incredibly fast towards the robot, so fast that she actually ran straight up its left leg.

She ran until she was at the chest area, and then she jumped off a bit before pulling off a fast and powerful roundhouse kick against the chest. However, she failed to do any sort of damage to it. "Such hardness!" she thought in shock before falling back down and landing in a crouched position, and then she jumped back to a safer distance.

"Gum Gum Gigant Pistol!" shouted Luffy as he jumped into the air while blowing air into his index finger to increase the size of his arm to a monstrous size, and then he unleashed his giant-sized fist at the chest of the robot. The attack struck that area hard and actually made the robot lean back a bit, but it ultimately didn't do any good. Luffy suddenly felt strength disappear from his fist before pulling it back and returning it to normal size.

Making his arm gigantic and turning it into mochi, not to mention it covering in spikes, Katakuri swung at the right foot, striking it hard, only to do nothing to it. He returned his arm to normal and said, "Tsk! Looks like it's going to be harder than it seems!"

The robot lifted its foot and slammed down hard, creating a shockwave that blew them back, but they also managed to retain their footing. It then pointed the shark head that it has for its left hand and fired a blast of energy at them. They all got out of the way, and the projectile created quite an explosion when it struck the ground, blowing them all away.

After landing from getting blown away by the explosion, Sabo propelled himself high and fast into the air by releasing fire from under his feet. Flying towards the robot's chest, he released a massive stream of fire at it. "Fire Fist!"

The fire didn't seem to do anything against it, other than making it glow bright red. The robot then swung its claw at him. Sabo expected to be unharmed by the attack, but instead, he was actually swatted away and crashed onto the ground.

"Sabo!" Luffy cried out to him in shock.

Sabo stood up like nothing happened, however. "Don't worry; that was nothing! But strange… It managed to hit me just now… Machines can't use haki, so the only explanation for that is…"

"That thing is coated in Seastone!" explained Law.

"Seastone? No wonder I felt my strength disappearing briefly when I punched it just now!" said Luffy.

"Also explains its hardness," said Katakuri. "They are some of the hardest substances in the world."

"Not every single part of its body is coated in Seastone," said Law. "I used Scan just now to get an in-depth look at its inner workings, and there are certain parts of the body that aren't coated with Seastone. Those are the parts we should be attacking!"

"Hurry up and spill it out," Crocodile told him. "Which parts are the most vulnerable?"

"The chest, hands, feet, and the anchor at the end of its tail all have Seastone coatings on them," replied Law. "All the other body parts are normal metal. We should be able to deal damage if we strike those parts."

"Okay, just avoid hitting the parts you said," said Luffy with a nod.

"We won't let you have your way so easily!" said the voice of Enterprise. The robot held up its flight deck, and life-sized jets materialized on it before taking off into the air.

"It's those flying things again, and they're bigger this time!" said Luffy.

"Witness the power of the planes of the Eagle Union!" shouted Enterprise.

The planes zipped around the air at fast speeds, occasionally diving downwards to shoot them with bullets. The pirates moved around fast to dodge them.

Blowing a kiss, Hancock created a large heart that she then pulled back its back to make it burst into a large amount of arrows. The arrows were strong enough to pierce the planes, partially turning them to stone and making them crash onto the ground.

"Fire Fist!" shouted Sabo as he unleashed a blast of fire to take out the remaining planes in the air.

Inside, Enterprise was surprised at what she saw. "Incredible…! They took out all the planes already!"

"The battle has only just begun!" said Bismarck. "Sooner or later, they're going to fall before us! No way are we going to lose with a size like this! Size matters!"

"Take this again! Gigant Pistol!" shouted Luffy as he blew air into his fist again to increase its size and then threw a giant punch. The robot folded its claws hand into a fist and unleash its own punch as well. The two fists came in contact with each other, and immediately, Luffy felt his strength disappearing. "Crap! The Seastone!"

Unable to hold up against the fist for that reason, the robot was able to push back against it and was close to crushing him against the ground, but Hancock charged underneath the arm and jumped up, kicking it so hard that the robot actually pulled its fist away. "LEAVE MY FUTURE HUSBAND ALONE!"

Crocodile and Jinbe also contributed to things. The former unleashed giant sand blades, striking the robot's arms, while Jinbe punched the air so hard that he sent forth a shockwave, hitting the robot in such a way that the vibration could be felt almost throughout its whole body. Even so, their attacks didn't do much other than putting a couple of scratches and dents on it.


While they battled, Arbiter was up in the air, watching the fight going on down below. "Fufufu! Those pirates are stronger than I think they are!" she said in interest. "A normal person would've been crushed by something the size of this in a second, yet they managed to hold up for quite a few minutes already! Coming to this world was worth it after all! By the way, I wonder how are things on the other end…"

Putting up a holographic screen, Arbiter looked for the status of the Siren ships she summoned, and she saw that quite a few had been destroyed. "I guess this is to be expected, seeing how most of Azur Lane is out there, and they know how to deal with this sort of thing."

Wanting to see how things are out there by herself, Arbiter moved her shark-like rigging in the direction of the sea. She was close to flying off the island when suddenly she felt herself stop moving. "Eh?"

All of a sudden, her rigging was pulled straight down through the air by an unseen force, much to her surprise, and hit the sand below hard. Arbiter took a few seconds to process what just happened before returning to her senses. She looked around in confusion at how she ended up in this place and then saw Fujitora and Alabama standing before her.

"Arbiter, the Siren Empress," Alabama said to her with intimidation in her tone.

"That's not very nice of you to drag someone to your doorstep without a warning," Arbiter said to them with a smile.

"So you are the leader of these Sirens, the enemies of Azur Lane's world?" Fujitora asked Arbiter.

"And what are you going to do about it?" Arbiter asked him.

"You and your people are being a threat to that world, and now you are bringing your reign of terror here? Is the lust for destruction and massacre so great that you feel the need to attack both worlds?" Fujitora asked her, his tone gradually increasing in intimidation.

"Now, now… No need to be so menacing," Arbiter said to him. "Because after all, your rage won't help you get through what you are about to face!"

"You have trespassed our territory, and for that, you will have to face judgment for your crimes!" Fujitora said to her as he readied his sword.

"Sorry, but nobody judges me! We Sirens are the ones who judge the fate of humans who venture out into the seas, because we rule over the seas!" Arbiter said loudly with an almost psychotic-looking face. The guns on her rigging then fired energy blasts in their direction.

Alabama was going to counter it somehow, but Fujitora held up his sword, which glowed with a purple aura that caused the projectiles to be diverted in different directions, so neither of them got hit. Without saying anything further, he slashed the air and unleashed a fast and relatively large wind blade in Arbiter's direction, but it disappeared when it struck a force field that was previously invisible.

"Impressive, but that's not enough!" Arbiter said with a smug look. She fired more energy blasts at them.

This time, Alabama charged at the incoming projectiles while swinging her scythe around at a fast speed, deflecting every single shot. She got up close to Arbiter and attacked with her scythe, but it struck the force field and failed to break through it. Fujitora also charged forward, striking the force field with his sword.

"You will never be able to lay a hand on me with your primitive weapons!" Arbiter said to him with confidence.

"Is that what you think of us? Perhaps it is true that we are primitive compared to the technology you have," Fujitora said to her, "but that does not mean we are weaker in power compared to you!"

The admiral continued to hack and slash away at the force field. Arbiter looked at the holographic screen to check her own status, and she saw that the force field was gradually showing signs of weakening. "Impressive! There is so much ferocity in his attack! I have to give him credit for it, but that is as far as he goes!"

The shark rigging moved back into the air. Raising her hand, Arbiter made missiles materialize all around her and then had them fly at Fujitora. Holding up his sword, Fujitora altered the trajectories of the missiles so that they flew in different directions. None of them hit him at all.

The admiral then leaped at Arbiter, thrusting his sword against her barrier hard before slashing it multiple times. "Is that all you can do? I can tell that you have unique powers, but if you can't make good use of it, what use is it?" Arbiter asked him with a somewhat mocking tone.

Fujitora landed and then sheathed his sword. "You continue to look down on me? In a battle, you should never look down on your opponent, whether he is blind or does not seem to have an impressive-looking ability."

"You sound like you have something up your sleeves," said Arbiter. She then noticed that Alabama was looking into the air with a somewhat expression and thus became curious. However, before she could look up to see what it was, a large rock crashed onto her rigging from above, striking it hard and sending it onto the ground. Arbiter screamed in shock and fell out of her rigging and onto the ground. The force field had to be activated by her voluntarily, and because she didn't know about the "meteor," she got hit.

"Did he… summon a meteor from space…?!" said Alabama in surprise.

Arbiter got back up and groaned a bit, and then Fujitora's blade was pointed at her neck. "Do you understand now?" the admiral asked her. "The moment underestimated the people of this world because we are not as technologically advanced as yours is the moment you raised your death flag!"

"I have to admit that you people impressed me more than I thought I would, but don't be so cocky of yourself just yet!" said Arbiter in a tone that sounded angry. Her rigging moved by itself and swung its lengthy tail at Fujitora, to which he responded by blocking it with his sword.

Arbiter used this short moment to hop back into the mouth of her rigging and then flew back to the sea. "She's getting away!" said Alabama.

"I'm not getting away," Arbiter told her. "Rather, I have something I would like to show you!"

Her rigging then glowed brightly in blue light while continuing to fly back and eventually diving into the water. The light died down a while later, and Alabama watched with curiosity at what would come next. "I sense something big coming," said Fujitora as he got into a defensive stance, which also made the ship girl wary.

Suddenly, there was a huge splash coming from the water, which rained back down to where those two are. A massive mechanical monstrosity resembling that of a sea serpent but with the head of a shark had appeared out of the sea. Though one can only see a part of its body sticking out of the water, it in fact has an incredible length of 300 meters.

Alabama had her eyes wide open at what she saw. All those who were close enough to see the mechanical sea serpent were shocked at what they saw as well.

Even those on the Thousand Sunny could see it. "What the heck is that?!" said Nami in shock.

"Is that a Seaking? But it's made of metal…" said Robin.

"Whoa man! That thing must've taken forever to make!" said Franky with an excited face.

The mechanical sea serpent lowered its head towards Alabama and Fujitora a bit and then let out a "metallic" roar. Arbiter was seen standing on its head. "Fufufu! Are you scared now?" she asked those two. "I may have underestimated you, but you shouldn't underestimate me as well!"

"So you've pulled out something, haven't you?" said Fujitora. "I almost wish I still have my eyes to see it, but perhaps I would regret it because of how atrocious it looks instead…"

"Trust me; you'll wish you have every single part of your body once I'm done with you!" Arbiter said to him in an intimidating tone.


TO BE CONTINUED

Arbiter gets her chance to shine! With the presence of two giant machines, fights are going to get wild! Hope you look forward to it!

And yes, there is a character in One Piece named Strawberry. Look it up.