Emi had disappeared for a few days, and everyone would have been worried if it wasn't for Sting's explanation. They all worked on their own spells and sparred with each other. Sting approached Laxus, and everyone looked on in anticipation and dread for whatever interaction they were about to have.
"Well?"
Light started whipping around Sting as lightning sparked around Laxus.
"Should we stop them?" Yukino asked worriedly.
Lucy spoke up as she turned to Levy, "Didn't you say that a fight between them would be to the death?"
She nodded and reminded them about how dragons would fight on behalf of their mates and that it would be a vicious battle.
"I wouldn't worry," Mavis soothed as she suddenly appeared by their sides. "Look closer."
They all turned back to the pair and saw that they were smirking at each other. Sting lunged first and when Laxus dodged, a huge crater formed in the ground where Sting's fists connected. Everyone sweatdropped and turned to Makarov.
"This might not be to the death, but should we still stop them?"
Thunderclouds began to form, and Laxus used his Breakdown Fist. Sparks began to fly everywhere, and another crater was formed.
Makarov spoke, "Let them do this for now. It seems to not be malicious at all."
"Holy Fire!"
Rays of light began to rain down on the field in the area surrounding Laxus. The lightning mage weaved through them and cast his Raging Bolt.
"Holy Fire? Since when can he use that?" Orga questioned.
"It must be a new spell that Miss Emi taught him," Yukino reasoned.
Laxus went to punch Sting, but he cast his Holy Nova, and everything was engulfed in white.
"You know, I've never actually seen him attack with that spell. He just kind of uses it as a blinding technique."
Mavis chimed in, "That's because the spell is very lethal and can cause a massive amount of damage, especially seeing as how much light he's been able to gather the few times that I've seen it."
Almost as if on cue, the light that Sting emitted began to shrink and concentrate into his fist. Everyone's mouths hung open and they whipped their heads to Makarov.
"Um, master? I think we should--"
Sting had landed his hit, and Laxus was forced back about a hundred feet. Rogue decided to try to stop the fight.
"Sting! That's enough."
The white dragon slayer looked over his shoulder, and everyone could see that his pupils were dilating rapidly. Mavis gasped. Everyone in Fairy Tail looked over to the First Master and asked what was wrong.
"I would suggest stopping the fight now."
Laxus had picked himself up and rushed at him again. He raised his hands to the sky.
"Thunder Downpour!"
Just as Sting's Holy Fire, lightning started to strike the field. Sting smirked and used his Holy Breath, cutting through the lightning.
"Holy shit," Lucy commented, "I didn't know that could happen."
They both stood eerily still, and everyone looked on to try to predict what would happen next. Makarov had started to step towards them to stop the fight before it escalated again, but Sting's light whipped around them again, blocking anyone else from entering the area.
"Did he seriously ask him to spar and then use the opportunity to try to kill him?" Cana shouted.
They saw Sting's teeth grow into faint fangs.
"Uh, we should really be trying to stop them, don't you think?" Lucy shouted.
"It seems that he will go for the neck," Mavis observed. "It'll be very effective if he combines it with a holy spell."
Suddenly, a flash of blue came rushing through the group and flew into the circle of light. Less than a second later, Sting was kicked in the side and went flying out of the circle. He was pinned by Emi's knees on his arms. The light died down, and Laxus was able to walk out of the area. He brushed himself off and returned to the group. Everyone stared at him.
"What? Haven't you ever seen two dragon slayers spar before?"
"That was not sparring young man!" Makarov yelled. "He was about to kill you. You should know better than to pick a fight with someone that has a vendetta against you. Especially a mated dragon slayer."
"What are you talking about? He was just testing his dragon techniques."
"...What?"
"But a dragon slayer only shows its fangs when it's ready to kill," Mavis interrupted.
"What? These?" Laxus asked as he caused his own fangs to form.
"Woah! How are you doing that?! You gotta teach me!" Natsu shouted.
"Besides, if he was really going for the kill, don't you think that he would've activated his Dragon Force?"
Cana asked, "Then why did Emi come rushing in like that?"
"Because," Emi answered as she glared at both Laxus and Sting, "I told them not to try it without me here just in case."
Sting rubbed the back of his head and Laxus avoided eye contact with her. She huffed and turned away from both of them before apologizing to everyone for the scare.
"Emi, will you please teach me that?"
"Natsu, it's not really something that'll be useful for you. You're most of a barge in and think later type of person. That dragon technique is more of a hunting technique."
"Aw man! I wanted fangs!"
Lucy punched Natsu and told him to start being serious.
"So how was your training?" Sting asked as he swung his arm around Emi's shoulders.
"Good. I'll be able to use a few techniques. Speaking of which, if you're not too tired from participating in a fight I specifically told you not to start," Emi sarcastically spoke, "then I would like to spar with you to work on your holy spells."
He grinned and playfully said, "I think I have some energy left."
It was Emi's turn to stand in a fighting position with Sting. Emi told him to cast one of his spells.
"Crown of Brilliance!"
Light whipped around before gathering into a ring on top of Sting's head.
"What kind of spell is that, First Master?" Makarov asked.
"It's an ancient holy spell that's used against demons. It makes the caster immune to unholy attacks."
"That's so manly!" Elfman yelled.
Sabertooth asked Makarov to explain what Mavis had said, and he quickly did so.
"I have no memory of such a spell existing," Rufus commented.
"Wait, but does that mean that Emi is gonna attack with...unholy attacks? What does that even mean?"
"Demonic Force Manipulation!"
Emi's body erupted in flames.
"Since when can she do that?" Gray quizzed.
The entirety of Emi's eyes turned black, and the flames turned a bright blue. Sting looked a little shocked himself, but he quickly shook it off.
"Demonic Force Manipulation," Mavis started, "is a forbidden spell that allows the caster to take on the appearance and abilities of a demon. I'm actually not surprised that she is able to so this type of spell given the fact that she is a demon slayer that was raised by a demon."
Emi started growling and lunged at Sting. He shot out a couple rays of light at her, but she easily dodged them. She threw her hands in the air and formed a ball of blue fire in her hands before whipping it at Sting. He jumped out of the way, and a bunch of trees caught on fire.
"Juvia," Makarov addressed, "do you think you could extinguish the flames before the whole forest is set on fire? Who knows how long this battle will be."
"Of course, master. Juvia will do it right away."
She quickly cast a water spell at the fire, but they weren't going out.
"No way," Levy gasped. "She's fighting with the flames of the Blue Demon?"
"Could this be the spell that she waited ten years to learn that we never got to see?" Natsu asked excitedly.
Another ball of fire went flying at Sting, and it grazed his pants and set them on fire. The fire grew, and Sting started to panic.
"Don't hesitate, Sting."
Sting came rushing at her while his clothes continued to catch fire. Emi sent a pulse of fire out and caught a ring of the field in the eternal flames.
"Sword Summon: Warblade of the Blue Demon!"
Cain's sword appeared in Emi's hands, and she sliced at the air in front of her without unsheathing it. A huge wave of pressure whipped towards the field. Sting was knocked off his feet. The group was pushed back about twenty feet from the pressure.
"How is she doing that? She spent three days alone and suddenly she's a demon?!" Gray screamed.
"This is very peculiar indeed," Erza spoke up, "but this will be a great power when facing the Sins."
Emi gathered a ball of fire in her hands again and was able to hit Sting dead on. Everyone gasped when Sting started to burn in the flames.
"Emi, that's enough. You must extinguish the flames."
The white haired woman slowly turned towards the voice and looked at them with a smirk on her face. Her teeth were bared and she continued to growl.
"Uh, First Master?"
"She might have lost some humanity along the way using this technique."
"Meaning?" Mira pressed.
Emi started laughing maniacally and formed a ring of fire around Sting.
"Meaning that she might have fully converted to a demon at this point."
"Come on, dragon slayer," Emi taunted. "I know you can do better than dodging."
Sting looked at the flames and gulped before taking a deep breath and walking through them. Everyone looked on confused when they saw that he wasn't being injured from the flames. They just seemed to burn on him, but he took no damage.
"That would be the Crown of Brilliance," Mavis explained. "The fire is a demonic attack, meaning that it would be nullified by Sting's spell. He won't be hurt by them."
"How isn't he getting hurt?" Orga questioned, oblivious to Mavis's explanation because he couldn't see her.
Levy quickly repeated what Mavis had said.
"You better hurry, Sting. I can't really keep this up for too much longer."
Sting shot light at her and used his Holy Nova to blind her. When the light died down, everyone saw that Sting had his hand on Emi's forehead.
"Angelic Exorcism."
A ball of light formed on his hand and shot into Emi. The flames extinguished immediately, and Emi's eyes turned back to normal. All of the fire that burned around them during the battle disappeared as well.
"First Master?"
"A holy technique used to purge unholy entities."
"I've read something about that spell," Rufus stated as he recognized the spell without the information from Maivs. "It can also be used with objects. It's exponentially more difficult to use it successfully on a living being, so I wonder how much practice he has."
Emi smiled at Sting and gave him a high five before turning back to the group.
"Why don't we all go relax for a bit? I'm beat. And also overheating. God."