A Railgun In Fairy Tail, The Diablo Saga: Book 3, The Will of Fire

Battle of the Hollow Dragons.

"LET GO OF ME!!!!" Mikoto screamed. "I HAVE TO GO SAVE THEM!!! MY BABIES!!!"

"You're... supposed..." Sakura growled as she barely held Mikoto back with her monstrous strength. "To recover... if you go into a big battle now... you'll pretty much kill yourself!!"

"We can't just blindly rush in!" said Mikaris, though she did look badly shaken. "He might just decide to kill them if it get's bad for him, we need to plan our approach. Lucky for us, he decided to use some home territory that's familiar for Sakura and Naruto.. "

"But there are tons of innocent people there too!!" said Sakura. "We can't just blindly rush in.. but.. there is something looking up for us..  I called a friend after he attacked me the first time.. he and Naruto are pretty much equals when it comes to how strong they are.. once he gets here, we'll have the advantage in strength and numbers.."

"But how can we tell if that's right!?" Touma exclaimed, looking extremely volatile now that his two daughters had been taken. "This is Kakine from the FUTURE!! Who knows how much stronger he's gotten in 8 years!? And he's somehow become an artificial Dragon Born!!"

"Natsu.. what do you think?" Erza asked. "Natsu?"

Everyone looked around.. but Natsu was missing.

"He didn't.." Erza muttered.

"Oh he did.." Mikaris said.

"That guy is like Naruto with pink hair.." Sakura said.

Miles away.. Kakine was flying through the night sky on his six wings.. he turned his eyes behind himself and smiled. "Oh? So he really is THAT tenacious? Oh Natsu Dragneel.. you are such a breath of fresh wind.."

"THERE HE IS!!! RIGHT THERE!!!" Natsu was riding on Kokuo, the 5 Tails as the giant tailed beast crashed through the trees, mighty power exploding from him.. galloping after Kakine with colossal speed.

"So you befriended one of the 9 tailed beasts?" Kakine called down. "Quite impressive, I'd expect nothing less of you Natsu Dragneel!"

"Heh!!" Natsu grinned. "I'm just getting started!! Go get em Mr. Kokuo!!!"

"Yes, you've got it.. TAILED BEAST BOMB!!!"

Kokuo began to charge up a black sphere..

"You sure you want to do that?" said Kakine. "After all, since I have these two!"

Kakine turned around, flying backwards in the same direction he had been going for a while.. showing Natsu and Kokuo the two infants in his arms.

"D-Damn!!" Kokuo growled.. as he stopped charging his massive chakra. "Lady Thundaarix's grandchildren!!"

"KAAAAKIIIINEEEE!!!!" Natsu screamed, now fully enraged, his body exploding with fire, his fists turning into flame gauntletts.

"Acnologia.." Kakine whispered.

At that moment.. a tremendous black dragon blasted out of the sky, roaring with fury before slamming it's talons into Kokuo's body.

"RRRAAARRGHHHHHHH!!!!" Kokuo slammed Acnologia off, firing a massive Tailed Beast Bomb into the dark dragon's chest, sending it flying.

"Don't patronize me dragon!!" Kokuo growled. "I'm not just some meager giant monster to be hunted and eaten!!!"

"Oh?" said Acnologia. "A strong opponent.. WONDERFUL!!"

Acnologia charged up a tremendous roar attack and fired as Kokuo fired another Tailed Beast Bomb.. the entire world shook within the light of the tremendous power that collided.