A Railgun In Fairy Tail, Diablo Saga 7: Finale Part 1.

Luffy and Yuriko

5 years ago...

"AHOY!! TO ADVENTURE!!" Luffy roared out gleefully as he grabbed hold of the Thousand Sunny's wheel, and turned it. The back of the ship had a banner saying 'Just Married' upon it, and Yuriko was laughing. 

"LUFFY!" Nami screamed, her head poking out from the ship cabin. "WHAT THE HELL ARE YOU DOING!? YOU'RE PUTTING US WAY OFF COURSE! JEEZ!!"

"Come on Nami, let him goof off  little, those two just got married." said Zoro. "Besides.. this ship is dimensionally connected to the Guild Hall, so if we get lost, we just go to Fiore and get a few drinks to wash out our sorrows.

"OH COME ON!" Nami roared. "At least TRY to care about what happens to the Sunny!"

"Nami give it a rest." said Zoro with a large yawn. "He's happy right now, happier than he's ever been, let him be."

As Zoro and Nami continued to argue, Luffy grinned at Yuriko. "So where do you want to go first? Mikoto told me we should go anywhere we want now to make it romantic.. however somebody does romantic stuff.. "

"My you're bad at this!" said Yuriko with a laugh. "But alright, how about we go visit that place where Gol D. Roger was executed, I hear it's a famous tourist spot."

"Auuuuuggghh!? But it's filled with Navy people!!"

"The danger makes it fun!!" said Yurko gleefully.

"Well said!!" Luffy said. 

"LUUFFFY!!" Usopp pulled Luffy aside, before smiling nervously at Yuriko. "J-just a moment please!!"

Usopp gave Luffy a serious look. "Listen Luffy! You're married now! You can't always act like it's fun and games anymore!!"

"Huh?" said Luffy.

"Luffy! A man's greatest duty first and foremost is to his wife!! Not even his superiors hold more priority!" Usopp said. "Which means you must protect your wife! Even if she says it's fine! you stick to her, through every moment, thick and thin! Have you seen Touma!? He's like glue with Misaka! And that's a lot given she's such a free spirit!!"

"Uh-" Luffy stammered.

LUFFY!!" Usopp glared into Luffy's eyes intensely. "SWEAR THAT YOU WILL DO WHATEVER YOU CAN FOR YOUR WIFE!"

"Of course-"

"SWEAAARR ITTTT!" Usopp roared, shaking Luffy's shoulders rapidly.

 "ALRIGHT ALRIGHT I WILL!!" Luffy stammered.

But Usopp needn't have begged.. for already Luffy felt an overwhelming desire to protect those that were precious to him..

__________________________

Present Day

"BUUU KILL YOU!!!" Majin Buu screamed as he hurled a powerful series of Ki blasts down at Luffy, who bounced out of the way, his Fourth Gear form using the elastic force in his legs to propel his inflated body through the air.

"GUM GUM.." Luffy's muscular arm retracted, building up intense elastic force. "Kong... GUUUUN!!!"

Luffy released the elastic build up, and his punch shot into Majin Buu's head.. There was an explosive shockwave, and Buu found himself hurling into the wall.. a few scrapes and injuries on his face. 

Buu stared at Luffy in some surprise. "y-you hurt Buu!?"

"ALL YOU NEED TO DO IS HIT HARD ENOUGH!!" Luffy roared. "You hurt Yuriko!! A Captain's first duty is to his ship.. but MY first duty is to my Wife!! GUM GUM.. . LEO BAAAZOOOKAAAAAAA!!!"