Thanks to Omegacrow and Aizakkuverse for the OCs, now before we begin,  

This fine piece of artwork of Omegacrow's OC is by Aizakkuverse, please note that never Omegacrow noticed that Kokoro's name isn't put in the normal One Piece way, Omegacrow put it as Kokoro D. Shiro when in the show Kokoro's name would've been Shiro D. Kokoro, so her nickname is "Storm Leg Kokoro", not "Storm Leg Shiro", I just need to clear up any confusion since the title says something different than what the picture says.

Anyway, on with the story! Enjoy!

With Ronnie Anne, she was currently dodging a series of near lightning-fast kicks from Kokoro, then Ronnie Anne flew into the air to evade another kick.

Ronnie Anne: Geez calm your massive ass! 

Kokoro:(angrier than before) F*CK YOU, YOU C*NT!!!

Ronnie Anne decided to retaliate, suddenly Ronnie Anne inhales deeply and her stomach expands great, then she slams her hand on her stomach, unleashing bullets of black and dark purple fire.

Ronnie Anne: Dark Phoenix Bullet!!

Kokoro yelped then ran away at high speeds by kicking the ground as she moved and leaving a trail of footprints in the ground, Ronnie Anne ran out of breath and went to take another large breath, but a spear suddenly rocketed past her, she looked to see Kokoro had taken a spear from an abandoned Marine cache labeled "Seastone Weapons", Kokoro then kicked open one of the crates, knocking the weapons into the air, before using a series of kicks to send the swords and spears rocketing at Ronnie Anne.

Ronnie Anne: Holy sh*t!

Ronnie Anne flew through the air to evade the weapons that were flying at her at supersonic speeds.

Ronnie Anne:(thinking) Just because I can resist Seastone's effects doesn't mean I won't get hurt from a blade made of the stuff!

Ronnie Anne was then grazed by a spear, Kokoro turned around to kick open another cache of Seastone weapons but she didn't notice a Seastone cannonball was falling toward her, that she knocked into the air too, Kokoro unintentionally bumped her giant rear end into it, Ronnie Anne landed but the same cannonball that bumped into Kokoro's rear end was launched past her, bearly missing her head, which then blew up a large house. Ronnie Anne looked at the few remains of the house and then at Kokoro, who wasn't looking at Ronnie Anne, but the Latina woman could tell that Kokoro's face was completely red with embarrassment.

Ronnie Anne:(trying very hard to not laugh) Did you... fire a cannonball... with your ass?

Ronnie Anne burst into a laughing fit, then Kokoro jumps into the air at the Latina woman and hit Ronnie Anne in the face with a powerful double foot stomp, nearly breaking her skull while forming a giant crater.

Kokoro: Double Quake Stomp!!

The island shook as if it was having a magnitude 10 earthquake, as did every other island around it, Ronnie Anne turned into black fire but Kokoro jumped away, only for Ronnie Anne to then charged at the thick thighed woman, then she flying forward while spinning towards Kokoro, whose eyes suddenly started glowing red, where she delivers a constant barrage of powerful punches that were blocked by Kokoro before leaping away into the air and flying right back at Kokoro with drill made of dark purple and black flames forming around her hands. 

Ronnie Anne: Phoenix Blaze Drill!!

But before Ronnie Anne could make contact, Kokoro seemed to recover, she then glared at the Latina woman.

Kokoro: Back Off!!!

https://youtu.be/eR3M8lteU-w

Ronnie Anne felt her forward momentum suddenly vanish and she felt like she was being pushed away, the Latina woman was sent flying back.

Ronnie Anne: Ow, bitch! Okay, let's try this!

Ronnie Anne created spiraling flames centered around her location before amassing it at the palm of her hand, Ronnie Anne then turns it into a gigantic fireball resembling a black sun and hurls it at Kokoro to try to obliterate her.

Ronnie Anne: Black Flame Bomb!!

Kokoro:(trying to think of something) Oh Crap, Oh Crap, Oh Crap!!

Kokoro then thought of something and sighed in defeat, Kokoro then launches herself at the black sun rear end first, then her butt somehow knocked the black sun right back at Ronnie Anne.

Kokoro: Moon Hip Missile!!

Ronnie Anne wasn't harmed by the massive black sun, but she couldn't see anything and as soon as she was able to see when the sun completely past her, she didn't see Kokoro anywhere. Kokoro had gone over to a large mountain of the island than with one kick she buried her leg into the mountainside, then effortlessly lifted the entire mountain before tossing it at Ronnie Anne. Ronnie Anne created spiraling flames centered around her location before amassing it at the palm of her hand, Ronnie Anne then turns it into a gigantic fireball resembling a black sun and hurls it at Kokoro to try to obliterate her.

Ronnie Anne: OH SHIT!! Black Flame Bomb!!

Ronnie Anne blew the mountain up but as soon as she did she noticed something, Kokoro had leaped into the sky as storm clouds suddenly form, channeling electricity through her right leg, coming down at Ronnie Anne with a nearly skull-crushing, electrifying kick.

Kokoro: Leaping Electric Kick!!

Ronnie Anne was knocked out by the kick, Kokoro took a minute to catch her breath, completely letting her guard down while a Marine with a battle-ax began to sneak up on her, then the Marine rose his battle-ax over his head and roared, but a young man suddenly stepped in between them, then performed a double spin kick, the first spin kick shattered the battle-ax and the second both shattered every bone in the Marine's torso and sent him flying.

The person was a dark-skinned young man in his 20s who had dark brown hairstyle in a ponytail with bangs and a lean muscular body with scars. He also has heterochromia, as the color of his right eye is brown and his left eye is hazel. He is wearing his father's trench coat but the sleeves are ripped off, dark blue fingerless gauntlets, black pants which his knees are also ripped off, exposing his knees, and black socks with waraji sandals.

???: Senpū no Yama no Ki!!

Kokoro: Oh hello again, El Sabio Luchador.

???: You know you don't have to use my nickname right? You can just call me Akira, Kokoro.

Kokoro: R-right.

'Akira':(looks at Ronnie Anne) It looks like you found yourself in a fight, I wish I could've been here to see it.

Kokoro: Trust me, wouldn't want to see me fight... Uh, could you help me carry her, I'd feel bad if I'd just leave her here.

Akira: Of course.

Kokoro and Akira continued to talk while Akira carried Ronnie Anne.

Akira: Out of curiosity, did you hear a loud scream earlier?

Kokoro: I was only hearing explosions from this woman and my ears are still ringing a little.

Akira: My manly instincts tell me that another man just took a painful hit to the groin.

Kokoro: Who would aim there?!

Akira: Someone whose a foul person or just has a crappy aim.

Kokoro and Akira continued through the town with Ronnie Anne.

That's all for this chapter, feel free to tell others who you'd think would enjoy this story, bye.