AN: Thank you AliceCullen3 and Wadeparker.
"Iron Dragon's Roar!"
"Demon Blast!"
Gajeel and Mirajane (in her Satan Soul form) attacked the Corpse Dragon with their magic, only for the torrent of shrapnel and beam of dark energy to transform into ash before it reached the dragon's body.
"Is your confidence starting to waver?" asked the Corpse Dragon, wearing a sadistic grin. "Is a sense of hopelessness starting to settle in?"
"Shut up!" yelled Gajeel. Unfortunately, the dragon's words were accurate. Not one attack had landed on the Corpse Dragon. Worse, Elfman, Lisanna, and Jet had been forced to stop attacking after the dragon reduced Droy's Plants to ash, revealing that its magic could also affect living organisms.
Only Gajeel, Mirajane, Levy, and Droy could even attempt to harm the dragon, not that they had much luck.
"Maybe… maybe if I try to eat its ash like I did with Rogue's shadows…" thought Gajeel desperately. However, he knew that was a terrible plan. He was more likely to be reduced to ash himself. Thankfully for the dragon slayer, one of his comrades had just come up with a better idea.
"That's it!" cried Levy. She looked at Gajeel. "I think I know how to overcome this dragon's magic! Get ready to attack!"
Seeing the confidence in Levy's eye, Gajeel smirked. "Gi hi hi hi! Then I better go all out! Dragon Force!"
As a scaly pattern spread across Gajeel's body and his hair grew spiky, the dragon slayer began to gather a large amount of Magic Power. He had learned how to activate the Dragon Force at will during Natsu's 'dragon slayer training' prior to the Grand Magic Games.
(On a side note, having missed the training, Wendy was now the only dragon slayer in Fairy Tail who could not use the Dragon Force on command. Excluding Blaze, obviously.)
"Let's hope this works," whispered Levy as she started casting her own spell. "Solid Script: Storm!"
The word 'storm,' written midair, unleashed a strong gust of wind on the Corpse Dragon. It looked at her with conceit, the Fairy's spell having no effect.
"I may not be able to turn air into ash, but it doesn't matter if you can only use magic as weak as that," berated the dragon. "This gentle breeze isn't enough to distract me from turning your allies' spells to ash, either."
Despite the Corpse Dragon's mockery, Levy didn't stop her 'storm' spell. In fact, his words made her smile.
"The fact that your trying so hard to discourage me just proves that my theory was right," she said with confidence. "Your magic isn't just ineffective against wind-based magic… your magic is rendered useless! After all, if you turn into or create anything from ash, it would just be blown away! Now, Gajeel!"
"Dragon Slayer's Secret Art: Karma Demon: Iron God Sword!"
Gajeel clapped his hands together and transformed them into a gigantic blade. He then swung this sword directly down onto the Corpse Dragon. A cloud of dust was kicked up as the two made contact. When it died down, the Fairies saw…
"Now do you understand that you humans have no chance of victory?"
…The Corpse Dragon, still standing. A decent-sized gash decorated its forehead, with blood trailing down its face. Gajeel's attack had definitely harmed it, just not enough. To defeat the dragon would take more attacks of that scale than their group had the Magic Power to perform.
"No…"
"Impossible…"
"It's Tenrou Island all over again…"
Seeing Levy's plan had failed to cause significant harm, the Fairies started to despair. This was what a dragon truly was. An immovable mountain that could only be conquered by another dragon.
"There it is," spoke the Corpse Dragon. "Now, which of you should I eat fir— Ahhh!"
The dragon's words were cut off as a surge of fire struck it. Having failed to notice the attack in time to avoid or counter it, the dragon could only scream as its flesh burned.
The Fairies turned toward the source of the fire, expecting to see Natsu. Instead, they saw a different dragon, wrapped in flames and being ridden by F-Blaze.
"Taste hell flames, asshole! Mya!"
Like her father often did, the young Dragneel's words and timely arrival filled her comrades with hope.
"Lightning Sky Dragon's Claw!" shouted Wendy, delivering a magically-enhanced kick to Zirconis's chest. As the dragon grunted and took a step back, she followed up with another spell. "Lightning Sky Dragon's Roar!"
"Gah!" went Zirconis as the attack landed. Several gashes were cut into his chest, bleeding lightly. He attempted to retaliate, only to lose sight of the dragon slayer as a swarm of fast-moving orbs filled his vision.
"It looks like your much weaker than Atlas Flame," stated Ultear as her spell ended and a single orb returned to her hands. "No battle instinct, either. I'm guessing you're the dragon equivalent of a couch potato… never fighting other dragons, just eating 'weak' humans. Fighting Laxus wore you down, and now Wendy's finishing you off."
"Shut up!" yelled Zirconis, swinging his arm at the woman. Minerva teleported in just long enough to get Ultear out of the path of his swing, causing the dragon to snarl. "All you've done is scratch me up! I'm more than powerful enough to kill all of you, if you would… just! Stand! Still!"
The dragon flailed around his body in a rage, determined to take out at least one of the infuriating humans. However, all of them avoided his rampage.
Lucy and Yukino summoned Virgo and Libra, who formed a hole for them to escape through. Millianna used her Nekōsoku Tubes to grab onto a thrashing limb and slingshot herself out of range, while Sorano had an angel fly her away. As for the Thunder God Tribe, they had already taken Laxus to Hisui and Arcadios for safety, guarding his injured body.
"Wait a minute!" cried Zirconis, pausing his outburst as he scanned the ground around him. "Where is that dragon slayer girl!?"
"I'm up here!" declared Wendy from above Zirconis. The dragon looked up and saw the Fairy surrounded by a whirlwind charged with electricity. "Dragon Slayer's Secret Art…"
"Crap," cursed Zirconis as the whirlwind began to descend around him. He tried to escape, only for the ground underneath him to collapse.
"Oh no you don't!" shouted Lucy and Yukino, whose Celestial Spirits had created the impromptu pitfall trap after they had retreated underground.
"…Shattering Lightning: Sky Drill!" finished Wendy, releasing a blast that pierced through Zirconis's scales and filled his body with an overwhelming amount of electricity.
"Aaaaah!" screamed the dragon as the lightning ravaged his internal organs. Once the last spark of it faded, Zirconis collapsed to the ground, unconscious.
As it turned out, a dragon was nowhere near as durable on the inside as they were on the outside.
"Fire Spin!" boomed Atlas Flame, turning into a flaming tornado that struck the Corpse Dragon in the chest. As the Corpse Dragon began getting pushed back by the attack, its body turned to ash, dispersing and reforming behind Atlas Flame.
"Why wasn't I able to reduce your fire to ash?" yelled the Corpse Dragon, feeling a mixture of rage and fear.
"My hell flames are hot enough to burn away magic as weak as yours," retorted Atlas Flame.
"Grr," growled the Corpse Dragon, angered by the insult to its magic. "If you're so confident about your magic, then try this on for size! Corpse Dragon's Utter Ash!"
A vortex of ash erupted around the dragon and shot toward his opponent. Several buildings were caught in this spell, all of which got reduced to ash in an instant.
As the attack approached Atlas Flame, F-Blaze (still riding him) piped up. "Let me handle this one, Uncle Atlas!"
"Very well."
"Mya!" cheered F-Blaze. Her expression then shifted from happy to serious in a heartbeat as she activated the Dragon Force. "Hell Flame Dragon's Nekomata!"
F-Blaze threw a large, spiraling, pinkish-red flame at the advancing ash. The spell, a combination of Atlas Flame's hellfire and her mother's Kitten Blast, erased the Corpse Dragon's attack.
"Impossible!" shouted the Corpse Dragon, unable to accept that a human had stopped his spell. This moment of stupefaction would prove to be fatal.
"Hell Flame Dragon's Roar!" bellowed Atlas Flame and F-Blaze, their spells combining and consuming the Corpse Dragon before it could react and defend itself.
"Aaaah!" cried the Corpse Dragon. When the flames faded, its scales were significantly blacker than they had been before, and a look of fear decorated its face. "This dragon is so powerful. And with all the damage I've taken… how can I possibly…"
On the sidelines, Gajeel gave his signature 'Gi hi hi hi.'
"Now whose despairing, you bastard!" laughed the dragon slayer.
Although the battle was not over yet, it was quite clear to everyone involved just who the victor would be. The difference between the two sides was insurmountable.
"White Dragon's Holy Breath!" yelled Sting, his White Drive and Dragon Force active. He fired an intense beam of white light from his mouth, hitting Scissor Runner. Sadly, the spell only left a small wound on the dragon's body.
"Pathetic!" responded the Blade Dragon, unimpressed. "What are you hoping to accomplish with suck weak magic?"
"Isn't it obvious?" replied the Fairy, grinning despite his failure. He looked at his allies, who were currently on the opposite side of the dragon. "I'm distracting you! Now, guys!"
Scissor Runner turned to observe Rufus, Orga, and the members of Blue Pegasus, curious to see what scheme they had concocted. The Blade Dragon didn't think that it would actually work but figured it would be amusing to watch.
"Memory-Make…" spoke Rufus. While Scissor Runner's attention had been on Sting, he had used his magic to imitate the Maguilty Sense used by Meredy. With it, Rufus gathered the Magic Power of the others to perform one big attack. "…Fire Dragon King's Roar!"
Scissor Runner's scowled as the dragon-slaying flames shot toward him.
"Blade Dragon's Rending Slash."
With those words, the dragon swiped one claw diagonally. Rufus's spell was split in two, the flames passing by either side of Scissor Runner.
"That one was almost impressive," sneered the Blade Dragon. The humans, stunned at how easily the spell had been stopped, could only listen to the dragon's derisive words. "I actually had to use my magic. Unfortunately for you, that imitation was nowhere near the strength of a Fire Dragon King. It wasn't even at the level of a regular Fire Dragon."
Rufus gritted his teeth as those words. He knew that he wouldn't be able to perfectly recreate the power of Natsu's spell, but he thought that he would at least be able to injure the Blade Dragon.
Scissor Runner began moving toward Rufus's group — who were still frozen in place by the dragon's display — prepared to finally kill Ichiya for his offense perfume, when Sting shouted at his allies and snapped them out of their stupor.
"Hey!" yelled Sting, cupping his hands by his mouth to help his voice carry. "I just thought of a Plan B! Follow me!"
The Fairies and Blue Pegasus mages exchanged glances, shrugged, and obeyed. They ran after the dragon slayer, who had started moving to their left (Sting and Scissor Runner's right). The Blade Dragon chased after them, though thankfully he was neither fast enough to catch up to them nor threatened enough to use his magic again.
Omake
Blaze, Asuka, and Iggy were looking out a window, hoping to catch sight of their parents fighting the dragons and dragon-like creatures. Behind them, Porlyusica was scanning the area for any signs that the fight was coming their way. It hadn't yet, but that could change.
At that moment, Blaze noticed a familiar figure flying through the air.
"Is that…" murmured the dragon slayer to herself. "…Uncle Atlas?"
With how quiet her voice was and how preoccupied the others were with their own searches, none of them noticed. Not until Blaze shot between Porlyusica's legs and out the door, racing toward the site of her draconic mentor.
Porlyusica reacted immediately, taking the other two kids and chasing after her runaway charge. Unfortunately for the medicinal advisor, a determined dragon slayer with a head start was difficult to catch up to. Especially for an old woman with two children in tow.
AN: I've actually come up with names for all the combinations of Millianna's spells and Hell Flame Dragon Slayer Magic. Nekōsoku Tube + Hell Flames is Hell Flame Dragon's Bakeneko and Nekōsoku Knight combines with her Flame Form to produce Hell Flame Dragon's Kasha. The latter is a layer of pinkish-red flames thinner than Flame Form, with cat ears and a tail.
That is all. Goodbye!