Male reader x Fem luffy

chapter 1

Y/n: hey let my sister go!

Thug1: and what are you going to do about it?

Thug2: Yeah shrimp what are you going to do about it?

Thug 3: forget him he's a weakling like his pathetic sister

Pudding: ...Please... stop--

Thug 1: shut up you little freak! *punch her in the face*

Thug 3: Finally peace and quite.

Y/n: I'll show you. YOU BASTARDS!?! NAGI NAGI NO SILENT COPY!!

And all of a sudden mochi came out of his body and was forming into a three section staff.

Thug 1: what the?!

Y/n: Take This!

Y/n fought the thugs and successfully saved pudding from the thugs and he placed his feet on one of them and began to heat up his leg as the thug was screaming in pain.

Guard 1: what's going on here?

Daifuku: Huh? *see's pudding* what happened here?

Y/n: I'm teaching this loser where he belongs.

Daifuku: Y/n... what happened to you?

Y/n: what do you mean?

Daifuku: i'll explain later for now carry pudding and follow me!

Y/n: Oh uh. Okay.

Y/n and Daifuku ran to up to perospero and katakuri who were with Smoothie and chiffon while y/n leaves a trail of burnt foot prints.

Y/n: Big bro! Big sis! Help us!

Perospero: What happened?!

Y/n: pudding got hurt by some thugs and she needs a doctor!

Chiffon: Give me pudding I'll get her to the hospital!

Y/n: Thank you big sis chiffon!

Chiffon and the others looked at y/n in curiosity and fear.

Smoothie: Y/n are you alright?

Y/n: what's wrong big sis smoothie?

Katakuri: you have mochi on your left arm and your leg is like ovens heat heat fruit.

Perospero: but I only gave him the nagi nagi fruit.

Smoothie: but he has big bro oven and big bro katakuri's power.

Y/n: I think I need a doctor?

Perospero: yes you should.

A few hours later

Doctor: I got some news Mr. Katakuri.

Katakuri: what is it?

Doctor: Turns out he has two devil fruit powers

Everyone: What?!

Smoothie: H-How?

Doctor: His second fruit is known as the Kopi Kopi Fruit is a really useless devil fruit but if the user has a second devil fruit abilities he can activate the hidden power of it.

Pudding: but isn't he supposed to explode?

Doctor: Yes but this devil fruit is so useless that it doesn't matter if you ate a different devil fruit because this devil requires the help of different devil fruit abilities.

Katakuri: so your saying is that it's basically harmless and If you eat a second devil fruit it won't kill you.

Doctor: precisely.

Oven: but how did he have it?

Cracker: he only ate one devil fruit.

Doctor: because the Kopi Kopi Fruit will change host until it's host eats a devil fruit.

Perospero: what do you mean?

Doctor: the Kopi Kopi Fruit will be passed down to the child of the user until the child has a second devil fruit ability and it will stop there.

Oven: So your saying--

Daifuku: he is the strongest in our family?

Doctor: Yes and no. The Kopi Kopi Fruit has a weakness. it will immobilize the user for 2 to 3 hours if the user pushed themselves to their limit.

Perospero: So he can fight anyone as long as he doesn't over work himself?

Doctor: Exactly.

Big Mom: Mamamama... My son is the strongest in the world. To bad for the side effects though.

Nougat: Amazing big bro you have a second devil fruit!

Flampe: Cool!

Y/n: I want to be cool as big bro katakuri.

Flampe: yeah you and big bro will be unstoppable!

Nougat: yeah and big bro peros can help you out.

Y/n: Alright I can't wait to train and see my potential.

Katakuri: I think I can teach him some of my techniques.

Perospero: And I can teach him how to balance out his powers as well.

Oven: He will be unstoppable force of nature.

Daifuku: I can see him being our best fighter.