So hey I guess. Uh well, I recently got into Blue Exorcist because of a friend. I thought Blue Exorcist and BNHA would go together well so I decided to write a crossover between them! I do hope you guys enjoy this first chapter.

This is set after the Kyoto Saga of the anime and right after the Stain arc of the BNHA anime.

Also, there's a fair bit of swearing in this chapter and throughout the story. Just figured I'd warn you.

Disclaimer: I do not own Blue Exorcist or My Hero Academia.

Rin stretched his arms out behind his head, taking a deep breath of the fresh night air. He had been out in the forest with Shura and Yukio for hours, and it was starting to catch up with him. The reason for them being out in the forest all afternoon was because they needed to hunt down some dangerous high-level demons, and Shura thought it would be good for him to get some field experience without the other exwires.

As fun as missions were, this one was intruding on his sleeping schedule, which was irritating him to no end. The half-demon already fell asleep in class enough already and a lack of sleep wouldn't help him stay awake, especially in some of the more boring classes.

Rin yawned again, this time louder, and caught Shura's attention. "You doin' alright, kid?" the scandalously clad woman asked, a hint of amusement in her voice as small smile formed on her face.

"Yeah, I'm just-" Rin was interrupted by another yawn, "-tired," he finished with another stretch.

Shura chuckled, bouncing her sword in her hand. "Oh come on! You can't be that tired, can you?" she asked, turning to face him with a lopsided grin. "After all, didn't you sleep through most of four eyes' lesson?" Shura couldn't help but laugh as Rin's sleepy eyes snapped open wide.

"I didn't sleep through the lesson!" he exclaimed angrily, glaring at the woman. The hybrid huffed and turned away as Shura's laughter only increased at his angry glare. "I was just resting my eyes, that's all," he added quietly from the side of his mouth.

The woman snorted. "Yeah for most of the class period!" Another laugh from Shura which earned another glare from Rin. Shura's fit of laughter wound down after a moment. "I know the chicken's class can be boring, but did you even try to stay awake?"

"Of course I did," Rin growled out irritably. How come Shura always had to get on his nerves?

The flaming-haired woman turned around, facing the path in front of her once again and slung her sword over her shoulder. She sighed before she responded, "I'm surprised." Shura could feel the daggers being glared at her and a few snickers escaped her mouth. Rin just made teasing him too much fun for her to resist, even on a serious mission such as this one. "Ya know," she began, catching Rin's attention, "I think you sleep about as a cat."

Her comment had completely offset the half-demon. "What?!" came his cry of surprise and irritation.

Rin heard her snort, telling him that she was messing with him out of her own boredom. They had been searching for a while now with no action besides a hobgoblin or two that had been attracted by a dead animal carcass, so it was no wonder that the two of them were starting to get a each other. "You heard me!"

He was about to protest to her insult when an idea came to his head. "Shura, are you drunk?" he asked in a genuinely curious tone. Rin was starting to think that the woman may actually have slipped a beer or two while he wasn't looking.

"Of course I'm not," the swordswoman answered nonchalantly. "But let's hurry up and find this Hellhound." A short silence followed her statement before another thought came to her. "I hope it doesn't chase you up a tree or anything." The swordswoman's lopsided grin had returned.

"I'm not a cat!" Rin protested, baring his fangs with fury. Shura turned around again, her grin never leaving her face. She knew he wouldn't do anything. He technically couldn't do anything to her as she was the superior sword wielder and he wouldn't dare use his flames on another person.

Shura chuckled at his anger. "You're not that far off," she pointed out with a shrug of her shoulders. "I mean, you've got the fangs, the tail, and you sleep a lot." Rin had hidden his fangs behind his lips when she mentioned them and checked to be sure his tail wasn't slashing at the air behind him like it usually would when he was frustrated. "All you're missing is a pair of cat ears!"

The half-demon growled at her teasings, coming close to baring his fangs once more. "Shut up!" was the only thing he could say. He was too tired to think of any clever comebacks. "I am not a cat," he pouted, ironically reminding Shura of an angry kitten.

"Aw, did I make the kitty mad?" she teased with a fake pout, effectively pissing Rin off even more. Before Shura could laugh at the half-demon's reaction, a black and orange blur darted past her, knocking her down onto the dirt path.

The forest had fallen completely silent now other than the chirp of crickets.

Finally the silence was broken when Rin asked, "What was that?"

The swordswoman quickly hopped to her feet, grabbing her sword off the ground, and said, "It must have been the Hellhound!"

The orange and black blur jumped out of the bushes and into the middle of the path. Before Rin could get a good look at the creature, it rushed at the two of them. Shura slashed at it with her sword, but the Hellhound jumped above the blade. It tackled her down before it charged Rin. The Hellhound rammed into Rin's stomach, knocking the wind out of him.

Shura pulled herself off of the ground with a grunt as Rin gasped to regain his breath. The demon snarled loudly before it bolted down the path to escape. "Ah, damn it!" Shura cursed. "The thing's gettin' away!" The swordswoman ran off after the creature while Rin got off of the ground.

"C'mon Rin!" Shura yelled over her shoulder.

"Oh damn!" Rin shouted as he realized that he was quickly falling behind. He ran quickly after his mentor and the demon she was chasing. He was catching up to them fast when something smacked him in the face.

The half-demon fell to the ground with a painful thud. He groaned in pain from the fall as he sat up slowly, holding his head. Once he opened his eyes, he saw what had knocked him over. It was a Goblin, a particularly big one too. It growled and snarled at Rin, hunching over in an attempt to look bigger.

"I don't have time for this," Rin growled, looking past the Goblin. He could barely see Shura in the distance and her form was only shrinking by the second. It seemed that she hadn't even noticed him getting knocked over.

The half-demon took a step towards the Goblin, causing its growling to increase. It didn't seem to keen on letting him get away. Rin grabbed Kurikara from his back, preparing to move the creature out of his way by force.

The Goblin snarled and lunged at Rin, its mouth wide open and prepared to sink its teeth into his arm. The teen swung the sheathed weapon at it, knocking it into a nearby tree. It didn't stay down for long as it was up and hissing at him in just a second or two. "Why do these things have to be such a pain in the ass?" he growled to himself as he swung at it again.

The Goblin dodged his swing and rammed into his leg, nearly toppling the teen once again. The creature took its long claws and slashed them into his shin, causing him to cry out in pain. He threw the demon off of his leg, panting. The Goblin rolled on the ground before it hopped up again. "Oh come on!" Rin cried in annoyance. Why wouldn't this thing just give up?

The Goblin let out an odd roar as it hunched over again. It was fairly obvious that it was ready for round two. Rin readied himself to swing Kurikara again as the creature charged him once more. As soon as it was in his reach, he swung the sheathed sword with all his might. The sheath collided with the creature's forehead and sent it flying into the bushes.

Rin stood in the path, breathing heavily as he stared at the bushes. He was expecting the Goblin to jump out at him at any moment and attack again. After a moment of nothing, Rin relaxed and let out a sigh. He put Kurikara back in it's sleeve and slung it across his back.

A painful jolt from his shin reminded him of the damage he had sustained during the little scuffle. The half-demon bent down and winced in pain as he looked at his shin. The pant-leg was torn and covered in blood. Rin could clearly see a few claws marks on his shin that were already shrinking. Being a demon did have its perks. "Doesn't look too bad," he commented to himself. The marks would be completely gone in just a minute or two.

Rin looked down the path. Shura was completely gone now. "Oh crap!" he yelled, getting to his feet. "I need to catch up with Shura!"

He began to walk down the path at as quick a pace as his leg would allow. "Ah, Shura's gonna kill me for falling behind," he groaned to himself as he wobbled down the dirt path. It wasn't long before the pain in his leg disappeared. Once he was sure that he could run, he began to sprint, hoping that he could catch up to Shura.

Any hope of finding the swordswoman was dashed when he came upon a fork in the road. There was no telling which way Shura had followed the Hellhound or if they even stuck to the path. After a few uncertain glances between the two different paths, Rin chose the left path, hoping that it would lead him to his mentor or his brother.

Rin dashed through the forest, looking every which way. He slowed to a jog when he spotted a clearing up ahead. Once in the clearing, he stopped. There was only one question on his mind: Where did he end up?

A deep growl from the bushes brought Rin out of his thoughts. He turned to the source of the noise and muttered, "Not another one." Rin's eyes widened when a figure jumped from the shelter of the bushes and landed in front of him. It was the Hellhound.

It looked a lot like a doberman, but its front fangs were much too large for its mouth. The bottom half of it was a deep orange color, and its eyes were completely red besides two black dots that Rin guessed was its pupils.

Rin froze in his tracks. If the Hellhound was here, then where was Shura? She was chasing it, right? Had she lost track of it?

The Hellhound let out a bark, gaining Rin's attention. "Easy, boy…" the half-demon eased. Normally Rin would be up for a fight, but he remembered what Yukio had told him about this demon. It was a high-level fire demon and even gave some of the most experienced exorcists trouble. Its fangs were sharp enough to pierce through metal, it could breath the flames of Gehenna, and in dire situation, it could set itself ablaze with fire. It could be weakened by holy water, but Rin didn't have any on him.

"Shit, what am I gonna do?" Rin's eyes darted around the area, looking for any way to escape the position he was in. Then he remembered. "The flare! If I can light it, Shura and Yukio can find me." He moved his hand down to his pocket slowly. The Hellhound's eyes followed his every move. The half-demon carefully pulled the flare out of his pocket.

Before he could light it, the Hellhound jumped and snatched it from his hand. It landed a ways away from him and chewed up the flare. "Aw, great," Rin muttered. He reached behind him once more and pulled Kurikara out of its sleeve. "I know Shura said to not use my flames, but I don't think I have much choice." He pulled the sword out of sheath. Blue flames erupted from the blade and from the end of Rin's tail as two horn-like flames floated above Rin's forehead.

What happened next was something that neither him or the Hellhound expected. A stark white portal appeared in the air above them, stopping each demon in their tracks. Rin gawked at the portal, unable to believe what he was seeing and thinking that it was just some sort of hallucination from his exhaustion. Something - or rather someone - fell out of the odd portal and landed on the ground with a thud, stapping Rin out of his surprised stupor. From what Rin could see, it was a boy with spiky blond hair. He appeared to be in a costume of some sort with grenade-like gauntlets, a jagged, black mask with flare-like ends protruding from the back, and a belt that held various grenades.

The boy pushed himself off the ground with a grunt. The first thing his eyes landed on was the Hellhound. It growled at the boy, saliva dripping from its fangs. To Rin's surprise, the boy only growled back at it. He hadn't expected that he could actually see the Hellhound, let alone not be fazed by it.

The demon, not happy about being challenged, rushed at the boy. Rin was about to warn the kid when the blond created an explosion to propel himself at the demon. Swinging his fist around in front of him, he created a large explosion from his palm, blasting the Hellhound away.

Rin stared with wide eyes, mouth agape. "H-how did he..?" Rin continued murmuring nonsense, which didn't go unnoticed by Bakugo.

"Will you shut up already?! You're reminding me of that shitty nerd with all your muttering!" he yelled loud enough for the whole forest to hear. His face was pulled into a snarl and his pointed eyes glared daggers at Rin.

Instead of doing what he asked, Rin bared his fangs at the boy. "What the hell's your problem?" Rin shot back with a glare of his own.

The other boy's frown deepened. "So the walkin' fire hazard can talk. I'm surprised."

Rin growled at the boy. "Who the hell are you callin' a fire hazard?!" the half-demon shouted, his tail slashing at the air wildly with rage.

"You, dumbass! That stupid tail of your's just caught a bush on fire!" Bakugo pointed behind Rin with his gloved hand.

Rin's angry glare quickly turned to a look of worry as he spun around to check if it was true. Sure enough there was a bush burning with blue fire. "Ah damn!" he cried, pulling his tail closer to him to prevent anything else from catching fire.

Bakugo watched him stomp the fire out with slight amusement. "Way to go, dumbass. You almost started a forest fire," he jeered.

As Rin stamped out the fire, it hit him that he had seen his tail and flames. "Crap! How could I have been so stupid?! Now this kid'll probably go tell everyone!" His panic only grew worse as he thought of what could possibly happen if the Vatican heard that some random kid with a temptait had seen his flames.

Rin turned to the boy and sighed. "Look, don't tell anyone about what you saw," Rin stated.

"Don't tell me what to do, dammit!" was his enraged retort. "Besides," he continued, "it's not like those flames are anything special, not compared to my explosions!" Man, this guy's ego was really starting to get on Rin's nerves. What wasn't special about Satan's flames?

Despite his desire to punch the guy in the jaw, Rin attempted to settle things without conflict. "It's really important that no one else finds out-"

"Finds out about what? Those pitiful little flames of your's?" Bakugo's lip curled into a nasty smile as he saw his words were succeeding in pissing Rin off.

"Don't test me, spiky hair," Rin growled out, a thin layer of blue fire surrounding the rest of his body. This guy was seriously pissing him off with all the trash talk and ego. Rin's short fuse also didn't help.

"The hell you call me, elf ears!?" he snarled, raising his hand and creating a small explosion. Rin guessed it was an intimidation tactic, but it had failed to scare Rin.

The name he had used, however, had managed to insult Rin. He was used to being called an idiot and a dumbass, but he had never had someone use his demon characteristics as a way to insult him. "I'm about ready to kick your ass," Rin warned, hoping that would get him to back down some.

It didn't. In fact, it seemed to spur the blond's anger. "You wanna fight me, then come at me, elf ears!" he challenged.

Rin growled with rage at the repeated name. "Fine then! Guess I've gotta kick your ass then!"

Shura took a deep breath and groaned loudly. She had lost the Hellhound that she had chased for a good fifteen minutes. To make it worse, she had lost Rin somewhere in the forest and not noticed, so she had to find him and the Hellhound she had lost. Man, tonight just wasn't her night, was it?

"I swear, I'm gonna strangle that little runt when I find him," Shura grumbled angrily. Her main concern was finding Rin. Trouble tended to follow the son of Satan around, and the exorcists didn't need a forest fire on top of their other problems.

A few gunshots caught Shura's attention. There was no doubt in her mind; it was Yukio. The swordswoman jogged tiredly towards the source of the noise to find the younger Okumura twin finishing off one of the Hellhounds.

He put his guns back in their holsters and turned to Shura. He expected to see Rin right behind her, but his brother was nowhere to be found. "Shura, where's my brother?"

The swordswoman sighed. "I dunno where the little runt ran off to," she answered honestly. "I've been lookin' all over for 'em and no luck."

Yukio took a deep breath and pinched the bridge of his nose. "That can't be good," Yukio sighed. "Where did you lose him?"

"I'm not sure where I lost him," Shura replied. "I was chasing one of the Hellhounds when I lost him though."

Yukio looked up to the night sky. "Hopefully Rin will be smart and use that flare. If he does use it, then we can find him easily."

Then they saw it. A bright blue light accompanied by occasional bright orange flashes. The two exorcists knew the blue was Rin's flames, but what about the orange flashes? Maybe it was the Hellhound? But Hellhound flames were typically red.

The two exorcists began to run towards the flashes. Whatever the other was didn't matter. All that mattered was that Rin was there. As they got closer to the bright blue light, they could hear the distinct sound of explosions. Now they definitely knew it wasn't a Hellhound.

They heard a shout of anger and someone's cry of pain. "What was it you said before? 'Guess I'll have to kick your ass?' How's that workin' out for ya!?" an aggressive voice roared.

"What has my brother gotten himself into?" Yukio thought exasperatedly.

Once the two broke through the treeline, they saw a boy with spiked-up blond hair standing on top of Rin, digging his boot into the half-demon's chest. Both of their eyes widened when they saw that Rin's tail tip was alight with blue fire.

"What the hell was he thinkin'!?" Shura muttered under her breath furiously. She had explicitly told him to not draw his sword unless absolutely necessary, and he drew his sword to fight some punk?

Before either could do anything, Rin's flames got noticeably hotter. The blond jumped off of him and yelled in pain. "Damn it!" he roared. "You little bastard!" To both of their surprise, the blond blasted himself at Rin, preparing to punch him in the face. Neither of the two had expected the kid to be able to create explosions.

Rin ducked the punch, and Bakugo landed not far behind him. Swiftly, Yukio took out his gun and slipped some tranquilizers into it. He aimed and shot two at the boy with both landing in his shoulder.

"What the-" Bakugo cried, glancing at his shoulder. His vision began to blur as he looked over at where the shots had come from. He could see two figures, one held a sword while the other held a gun with smoke coming out of the barrel. "Damn…" was the last thing that slipped out of his mouth before he fell over and passed out.

Rin looked at his brother from where he stood, panting. He hadn't expected the kid to know how to fight so well, but he had sure given Rin a run for his money. "Thanks," Rin rasped out.

"What the hell were you thinking!?" Yukio raged, putting his gun away.

"I told you not to use your flames, ya dumbass!" Shura joined, her hands on her hips.

Rin looked between the two angry exorcists. "I had too!" he defended, his hands in front of him in surrender.

"You had to use them to fight some kid?" Shura asked incredulously.

"No! I ran into that Hellhound you were chasing! That kid blasted it to kingdom come with his explosions before I could use my flames," Rin explained.

The two glanced at each other. It made sense. They had seen the kid create explosions from his palms with their own eyes, and Rin didn't pull Kurikara for just anything. The half-demon was aware how important it was to keep his status as Satan's spawn a secret.

Finally Yukio sighed. "I guess that makes sense," he stated reluctantly. It really didn't make sense, but what else could he say when he saw the kid create explosions himself?

Rin sheathed Kurikara, stopping the blue fire that surrounded him. "I'm glad you believe me, Yukio," he said. "I know it sounds crazy, but-"

"We already know, Rin" Shura interrupted lazily. "We saw him in action."

The half-demon turned his gaze to the now incapacitated blond. "Well, what should we do with him?" That was the million dollar question, wasn't it?

"It would be smart to bring him back to the school with us," Yukio spoke after a moment of silence.

"You're not serious, are you?" Rin questioned as he stared at his brother.

"I am," he replied, pushing up his glasses. "We can't just leave him here. And he saw your flames." Yukio pointed a finger at Rin. "And he can create those explosions," the spectacled teen continued. "We need to find out how he does that." As usual, Yukio had a good point.

"Alright then," Shura began, "let's get going." The swordswoman yawned loudly. "I'm beat."

Goodness, this was a lot longer than I anticipated. Uh, well I hope it was an enjoyable read for you guys. The next chapter might take a while since it's the final quarter of school, and they like to swamp us with work. I'll try my best to get it out soon though. I hope you enjoyed reading and until the next chapter.