A/N The Blue Exorcist and Granblue Fantasy crossover no one asked for :P (This is AU for Blue Exorcist)

A youthful blue-haired girl in a white dress stood in front of the stairs leading up to True Cross Academy. Rin paused as he did a double-take and then immediately bolted toward her. "Watch out! There's a demon on your head!"

Startled, the girl looked up and turned towards him. The thing on her head looked equally shocked and both backed up as he readied his trusty katana to dispose of the threat. "D-D-Demon? Where?" The panicked girl cried, looking around with worry.

"I don't see no demons!" The demon on her head said as it too looked around.

"Maybe he's mistaken?" Her gaze shifted from the thing (lizard?) on her head towards him, uncertainty in her eyes.

"Isn't that a demon?" He asked, now bewildered himself.

"Oi! I ain't no demon!" The lizard said. "I'm Vee!" It crossed its arms and flew up jerking its chin upwards in pride.

"What's a Vee? Is that a kind of lizard?" He asked and the blue-haired girl giggled. A beautiful smile graced her face. Her companion fumed.

"I ain't no lizard!"

"Vee is just Vee. He doesn't like it much when people call him a lizard." She said by way of explanation which didn't help him much at all. But it seemed to calm Vee down.

"Oh alright. Sorry for the confusion." Rin said and rubbed the back of his head. He sheathed his sword and slung it back over his shoulder. Yukio and their dad would scold him for slipping up in public like that. He glanced around and was relieved that there weren't any other people in the area. No one 'normal' had heard him shout about demons. At least probably no one heard him. But he did feel bad for startling them like that.

"So, uh, what're you doing here?" He asked her instead. He realized she'd been holding a map of sorts in her hand. "Are you a tourist?"

She shook her head, still smiling at him. "Nope! I came here to meet someone. You remind me a lot of him." It was a warm smile and also a little mysterious but he couldn't bring himself to even think that she might be hiding something dangerous.

"Do you know where this person is? I could show you to his place. I'm pretty familiar with the area." He grinned at her.

She was about to answer him but a loud rumbling and low squeaking interrupted her. A blush spread on her face and she pressed a hand to her stomach. "Ehehehe… I'm sorry. I guess I'm pretty hungry."

The lizard just shook his head. "Jeez! I'm not even surprised anymore after knowing you for so many years." The girl laughed sheepishly in reply.

"I could make something for you if you'd like. I do want to apologize for scaring you. My dorm's just over there." He pointed with his thumb. The two happily agreed to come along and so a few hours later they were sitting in the cafeteria of his dorm, chomping down on a home-cooked meal. He was kind of shocked by how much she could eat after he'd assured her she didn't have to hold back.

"This is so delicious! Thank you so much, Rin!" This gave him halt.

"I'm glad you liked it… How did you know my name?" He asked her.

"Oh, I guess we got side-tracked earlier. I've been looking for you. I came here to meet you." He stared dumbly at her as he tried to process this.

"For me?" He repeated and she nodded. "Why?" He asked. Apprehension was starting to creep up his spine. The only reason people ever looked for him specifically was because of his heritage. But although past experience told him to be wary he felt completely at ease around her. It was a weird feeling, like some sort of connection. But he was sure he had never seen her before.

The smile slipped from her face and she fisted her hands in her dress, worrying her lips. "I'm sorry, but I can't tell you yet."

He wanted to protest but Yukio barged into the room, out of breath. It had to be urgent. He was halfway out of his seat, sword in hand before his brother caught his breath. "Rin, there you are! We need all the exorcists in the area! A huge swarm of demons has shown up out of nowhere."

"Even the Exwires? It must be serious." There were a lot of exorcists stationed at True Cross Academy. It did also serve as the main exorcist headquarters in Japan after all.

Yukio grimaced as they sped down the corridor. "They want your help. Conventional methods aren't doing much against these demons."

Rin's mood darkened. He understood. They wanted him to use his speciality, the blue flames.

"Wait-!" Both of them stopped to see the blue-haired girl - Lyria, she'd introduced herself while chowing down on his food - hurrying after them. Yukio's gaze darted from him to her as if, in his haste, he hadn't noticed she had been in the cafeteria with him.

"Stay here, it's not safe." He commanded and turned around marching forward again.

"B-But-!" She protested and Rin shot her a pleading look.

"We'll be right back!" He yelled behind him. The two brothers ran off, too fast for the petite and already out of breath girl to keep up with.

On their way to the central plaza one of those demons Yukio told him of jumped in their way. His brother drew his guns and shot before Rin could even blink at the thing, years of experience had shaped his quick reaction. But instead of exploding into black mist like a demon of its size normally would, the bullets dug themselves into the demon and it turned its ferocious eyes on them with a howl.

Rin fisted his hand until he felt the spark of his flames in his palm. The demon lunged at them, wolf-like maul ready to snap around bones. Rin slammed his palm forward and the demon's head exploded in a blue flash of light, even as it collided with his hand. It released a sickening shriek until it burned up into ashes, the flames licking at his hand. There was the usual black mist he was familiar with from Yukio's exorcisms that he'd watched but it had never smelled like that. It had never smelled like anything before. He backed away from the stench.

He'd never seen a demon die like that. It made his stomach churn. His breaths came in harshly as he tried to regain his composure. Yukio looked worried. "Rin, are you alright? Don't force yourself. You haven't used them on actual missions before."

Rin shook his head to clear his mind and waved his brother off. "Come on, this is no time to be dawdling!" He then broke into a sprint, rushing off towards the plaza, Yukio hot on his heels.

They encountered a few more of the weird demons on their way. The flames came easier each time but they were also exhausting him. Yukio hadn't reprimanded him but he could see the worried glean in his eyes. If the situation weren't so dire, he'd probably have been forced to return to the dorms after the second one.

The situation as they neared the plaza was chaotic. There were hundreds of those things. Groups of exorcists ganged up on individual ones while others tried to break the enemy's formation and lure individuals out. The Arias' chants were doing little more than distracting the demons and those who could were doubling as medics. Dragoon squads emptied entire batteries of shells at the horde just to hold them back. The Knights were busy cutting down the individuals, their corpses strewn across the place. Really… Since when had demons left corpses behind?

"What the heck…" Was all he could mutter as they made their way in.

"Try setting your sword on fire, Rin. That might be less strenuous in the long run." Yukio said. He'd adjusted his glasses again. Rin nodded though he wasn't sure that was actually something he could do. There wasn't a better time to try than the present though.

Drawing his sword, he held his other hand just above the hilt. The flames sparked and he ran his hand down the length of the blade. It caught fire as he did so and glowed in the heat. Exorcists nearby flinched away but settled into their formations again when they realized the flames were on their side.

Only legends and old stories from centuries ago spoke of Satan's blue flames. It was really a wonder that the fear of it was so ingrained and had persisted until this day.

Rin swung his blade, its path lighting up as the flames dragged behind it. It sliced through one of the beasts like a hot knife through butter. The flames caught on and burned up what hadn't been cut apart. He clenched his jaws forcing himself to move on to the next one.

Yukio was always at his back, managing the crowd of demons so he could focus on only a few at a time. Hack. Slash. Move on. Hack. Slash. He had to reignite the blade from time to time but it was easier than throwing raw flames at the demons. But the sheer number of foes was overwhelming. A few broke through and gave him some gashes before he could incinerate them. Deep down he knew he wouldn't last. The flames within him had never felt so dim. As he panted for air, he felt Yukio at his back.

"We can't go on like this. Let's make our way to father." Rin gave him a sharp nod and then slashed his sword through the air, burning open a path for them. They made their way down a more fortified street as other exorcists covered their retreat.

They found their dad at the back, pointing fingers and shouting orders all while treating wounds and studying the town's layout. "Hey boys. Good work out there! I've already heard some reports." His tone was light but the smile missing from his face. It made everything feel worse than what he already knew it was like.

He felt foolish for wanting a break. Others were working themselves to the bone. "Dad, I-" He started but Yukio cut him off.

"Rin can't go on like this." Rin protested but his twin shot him a glare. "This is crazy. He hasn't even had much experience. He shouldn't be on the front lines like this. His flames are wearing out."

Dad frowned. It was a knowing frown. He'd known that Rin wouldn't be able to be their 'saviour' right now, not yet. Heck, he didn't even want Rin in the exorcist business, his father had said that much time and again. He had been against it, he could see it in his eyes. This had been someone else's idea. Someone else's expectations pushed onto him.

Rin didn't know what to feel. He hated feeling special, but special was all he'd been since he'd been dragged in front of the Grigori. He'd promised them to be their special weapon to protect his dad from the punishment he was about to face for harboring the son of Satan for fifteen years. He felt like he was letting himself down more than the Vatican but at the same time it was reassuring that his dad didn't expect him to perform a miracle, didn't expect him to outperform Yukio who had years on him where exorcism was concerned.

"If he's running out of steam, he should draw the sword." It was Angel. Rin hated that guy's guts. He still hadn't forgiven him for running his blade through his leg to 'keep him complacent' during the hearing. That had hurt like hell and taken weeks to heal. Yukio glared as well, having his own grudge against the narcissistic man for his aggressions against Rin.

Dad's expression turned dark though he continued his treatment of the man at his feet. "Absolutely not." He hissed and it was Angel's turn to glare. Rin didn't miss the fact that the man had brought Kurikara with him. So they intended for him to break the seal no matter what. Telling his father of it was only a formality.

He reached out his hand, waiting for the man to give him the damned blade. The Knight had the gall to smirk as he passed the sword to him. "Good boy. Much more obedient than your father." Rin growled but resisted the urge to bite him.

"Rin, you can't seriously be thinking about drawing it! We don't even know if you'll be able to control it!" He could hear and feel the fear in his dad's voice. It made his own fears rise up in his throat only to be swallowed down again in a loud gulp.

He forced a grin. "It'll work out. I've been training hard after all!" He rushed out of their makeshift center of command, Yukio and his dad following closely. Despite everything, Yukio releasing a string of curses under his breath put a smile on his face.

He ran past Bon and Shima as he made a beeline towards where the demons seemed to be emerging from according to the map his father had been studying. He didn't stop and it was only an instant but Bon had recognized his family's keepsake, realized what he friend was about to do and looked horrified. "Rin!" He shouted after him but Rin didn't stop.

He only stopped when he reached the wall of dragoons, skidding to a halt behind the line where they fired in three rotating waves to give each wave time to reload. In front of them, a giant portal-like hole spat out demons nonstop. His hands shook and his own fear clawed at his heart again. The hammering in his chest was making it hard to stand still. He raised the sword and as if it were reacting to him it seemed to pulse against his hands. Or maybe his pulse was thudding against the motionless sword.

He was going to draw it, claim his heritage and return the demons to the hell they belonged in. If only it weren't so hard to breathe all of a sudden. Damn it. He'd drawn swords hundreds of times before during training and even in combat. This shouldn't be so difficult!

Yukio and his dad were behind him, shouting at him to stop, that he couldn't go back once he'd taken that step. They couldn't stop him though. A wall of blue fire kept them behind him. When had he even summoned that? He'd take that step for them. He'd do it, damn it! He squeezed his eyes shut, grip tightening on the hilt and sheath in front of him.

It was the voice of a girl that stopped him and tore him from his spiralling desperation. He snapped his eyes open and whipped his head to where her voice had come from only to see her jumping through the flames as if it were nothing more than tall grass in a spring meadow. "Don't do it!" She shouted and practically rammed into him.

"What're you doing here?! You should have stayed where it was safe!" He wanted to scream.

"Humpf! We're here to save your ass, that's what!" The flying lizard said, a cocky grin on his snout. Rin didn't know how to respond to that but Lyria grabbed his attention and his hands, clutching them tightly in hers, having no regard for the blood from his cuts that now stained her hands.

"Please trust me." She said and her voice was so calm and so strong, he felt himself relinquishing Kurikara to her before he knew what he was doing.

"Wait what're you doing with that?!" He asked. Her reply was that same mysterious smile from earlier.

"Trust me." She repeated and he faltered, staring as she took up a firm stance and faced forward with determination. She raised her hands, arms straight and palms open wide. Kurikara bobbed gently in the air, resting on the pure energy that he could feel gathering around her.

A ring of light lit the ground, symbols he didn't recognize decorating the array. Was she a tamer? He discarded the thought as soon as he'd had it. He'd never seen a summoning like that before.

"Come forth!" She said. Her voice was commanding. If she'd asked the stars themselves to move they'd obey her, he was sure.

He stared in awe as the light consolidated around Kurikara and formed a vaguely human shape. Then it became too bright to look. When the light subsided what appeared to be a young man clad in armour and a tattered hooded cape stood before Lyria, gripping Kurikara lazily across his shoulder.

A mask covered his face and Rin didn't know him well enough to read the expression in his eyes but he'd guess it was… Excitement? Another part of him was distracted with the fact that this man felt familiar. His entire being knew this man's presence. He had a sinking feeling in his stomach as a pair of intense brown eyes settled on him. It was weird, they looked nothing alike but it was like facing himself.

He wanted to shrink away.

Facing a self that was a thousand times more intense and intimidating, that is. He knew who this must be. And as if to prove his theory, without even looking behind him, he waved a hand in the air and everything burst into blue flames. There were no howls, no shrieks, ash clouded the sky before there was any chance of that. The only sign he was even expanding any effort was the red gleaming in the depth of his eyes. Rin knew his own eyes shone like that when he used his flames.

And still the man's gaze was levelled on him, inspecting, judging. He sunk to his knees, feeling overwhelmed. His own voice echoed in his head, mocking him. As if he could ever defeat someone who was so powerful, he'd wiped the entire battlefield, burning every single one of their enemies with efficiency and precision. And he didn't even look like he gave a damn. The title "God of Gehenna" was starting to make a whole lot of sense to him.

"S-Satan…!" Someone shouted in panic and levelled his gun at the figure. It trembled violently in his shaking hands. It would take a miracle for him to hit his intended target.

The man half-turned at the voice and a look of annoyance crossed his eyes for only a moment and then the expression was gone again, like he'd played this game one time too many. Lyria looked confusedly between her summon and the exorcist, tilting her head to the side as she did so. He raised his hand and Rin felt cold dread sweep across him. He was sure the exorcist would be executed.

But it didn't happen. The wave he'd felt had spread, forcing everyone in the area to their knees, like he'd upped the gravity with that one gesture.

The exorcist's gun dropped to the ground, where he lay. He wouldn't be able to retrieve it if he wanted to. Though it appeared he was trying his best to reach for it, one centimetre at a time.

A slap echoed across the now silent area and Rin tore his eyes away from the struggling man and back to 'his father'. Had Lyria just… slapped him? The man removed the mask covering the lower half of his face to rub at his sore cheek. The pout he wore instead clashed violently with the image he still had in his mind.

"Gran, you're scaring everyone! What are you even wearing?" She sounded so exasperated it bewildered him. Also… Gran?

"Huhu, Gran always knows how to make a dramatic entrance. Yo! It's been so long, hihihi!" Vee chimed in, his voice full of pride. A huge grin broke out on Gran's face as he reached out and plucked the lizard out of the air to snuggle him, like a child would his favourite stuffed toy. Vee's protests were ignored.

What was even going on? He could only watch the scene numbly. It felt like a family reuniting after a long time.

"Oh, that's right! I have to introduce you!" Lyria bounced up and down in joy as she dragged the man toward him, a bright smile on her face all the while. "Gran, this is Rin. Rin, this is Gran, your dad!"

Gran frowned at her briefly and pinched her cheek, then gave him a small smile. He held out Kurikara to him, motioning him to take it.

Rin's hand shook as he grabbed hold of it. He wasn't sure what to expect. When it was securely in his grip, he realized that Gran had let go. Or rather he didn't have the hand to hold it anymore.

His hand was fading, like the rest of him, returning to the particles of light Lyria had summoned him from. Gran waved at him but he was too out of it to do more than stare at the fading figure.

Lyria's smile turned wistful. "Bye." She said, waving toward where Gran had stood.

When he was completely gone, the gravity around them started returning to normal and the exorcists scrambled into motion, wearily aiming at the harmless girl.

"Oi, oi! What do you think you're doing!" Vee shouted at all of them, flying in front of her protectively. His paws curled into fists.

Rin was still trying to process the fact that Lyria claimed his dad was not called Satan but Gran and that though he'd been told otherwise the last year and he'd only just met her, he trusted her word over everyone else's. But he stood up anyway to shield her from the muzzles of the guns aimed their way.

"Stop! Lay down your arms!" His dad's commanding voice cut across the clamour, though he looked weary himself. The exorcists hesitated but did as they were told. Only when the last gun was lowered, Rin felt himself relax. "I'm sorry little lady but you have to understand that we're very confused as to what just happened and you'll have to come with me for an interrogation."

"Sure! We didn't get to talk properly earlier anyway." She smiled at Rin again and held out her hand to him. Even though everything just seemed so crazy right now, he took her hand. It was warm and comforting and it kept all the questions and mistrust in his head at bay. He felt like a child again, protected from the outside by a parent's hand guiding him. His dad led him, Yukio, Vee and Lyria through a door, bringing them back to… Their dorms?

"What're we doing here, dad?" The cafeteria was exactly as they'd left it. The old man took a seat and motioned for them to do the same.

"I thought this was the best place to keep away from eavesdropping ears for a while." He steepled his fingers and faced the blue-haired girl. "I should thank you for stopping my son from breaking the seal on Kurikara but I need you to tell me everything you know." Rin winced a little at his dad's strong emphasis on 'my son'. He'd obviously heard that last bit and was feeling uncomfortable with the situation.

Lyria didn't look bothered by that fact. She was bothered by something else however. "Uhm… What do you mean by everything? I know quite a lot of things but it's not like I really understand it all either." She broke off in a mumble. Rin realized she was still holding his hand as it squeezed a little, searching for reassurance from him.

"Why don't you start by telling us why you think 'Gran' is the father of my twins." His tone was calm but Rin knew that his dad was unnerved that such an unassuming girl could summon a being so powerful.

Lyria tilted her head to the side, thinking of how to answer him. "How? Well, he just is?"

The paladin's expression hardened at the unhelpful information. "It feels like I know him. She's definitely right!" He piped in, hoping to keep everyone even tempered. Well, mostly his dad. Yukio looked calm. In fact, he was surprised when he nodded along.

"I could tell too." Their dad looked between them, bewilderment on his face.

"That reminds me, what was up with that guy shouting Satan at Gran?" Vee asked, he'd sat himself on the table in front of Lyria after nabbing an apple from the kitchen. "Satan and Gran look so different, anyone should be able to tell them apart! I mean, Satan's not even a human."

The old man pinched the bridge of his nose. "You're trying to tell me Gran is human?"

"Yup, why wouldn't he be? Gran is just Gran." Vee said and then took another bite out of the fruit.

"Ah, well, he lost his body a long time ago. That's why he's forced to live on the other side. I guess that's not quite human?" A sad look crossed her face. "He had to do it to save the Skydoms from a terrible Primal Beast. He said he was okay with that, but it's coming back and I need Rin's help!" She shot him a pleading look but he recoiled at that.

"Hold on, hold on! What Primal Beast?" His dad asked, drawing her attention back to him.

"Oh I'm sorry, I got ahead of myself there." She proceeded to explain the monsters they'd just fought and how it related to the Primal Beast to Yukio and their dad. Rin wasn't paying attention. He felt a little hollow inside, why did it always come down to his heritage. Even if his father wasn't Satan, it hadn't changed the fact that whoever he was, he was really powerful. And he had the blue flames. And someone always always wanted to use him. He hated it. He felt like a tool.

"Rin, are you alright?" Lyria asked him. He blinked at everyone around the table, cursing in his mind as his vision swam. He blinked away the tears and looked away.

"I'm fine." He bit out. But she seemed to know what was bothering him anyway.

"You don't have to do anything you don't want to." He turned back to her sharply. Wasn't she just saying a minute ago how she needed his help? She laughed lightly at his expression. "Gran was right when he said you looked happy here. I'm so glad you have such a kind father looking out for you. But it wouldn't have been right if we didn't tell you about us at all." She paused a bit as her face flushed. "So I've been searching for you both all this time to ask you if you'd like to come with us. You really don't have to do anything you don't want to though. Really, really. We've always managed to find a way after all!" By the end she was waving her hands around frantically.

"Wait, but what about Yukio?" He was changing the topic but he needed to get a grasp on the whole situation before he could even begin to think of an answer.

"Yukio has a different set of Gran's abilities. He can help too if he wants of course. But to seal the Primal Beast, Gran has to come back to this side. He'd need to possess someone or I'd need enough of your blood and Kurikara to summon him for a longer period of time. And we can always look for another way, of course!"

Their talk was then interrupted by a door on the ground floor slamming open. Angel could be heard commanding exorcists to infiltrate and capture the blue-haired girl.

"Not this again!" Vee whined. "The Empire was bad enough."

And then his dad shoved a key at Rin and pushed him, Yukio and Lyria towards a door. "Go! It'll take you to the guard house by the bridge!" He smiled at them. So, he'd made up his mind about where he stood in this situation already.

They fled out the guard house under the cover of night, crossing the bridge to get out of the immediate area where exorcists were sure to be concentrated. Kuro pretended not to see them passing by. At an intersection, Vee took the lead and steered them towards a harbor, where an outlandish ship was docked. They made a beeline for it and hid within.

"One question." Yukio asked when they had hidden in the insides of the large vessel until the footsteps and commotion of searching exorcists had subsided. "How is it that we're part demon if Gran is a human?"

"Uhm… I don't know?" Lyria answered, smile tugging at her lips. "I only know that you both have part of our soul. I don't know how it happened."

"Our soul?" Rin asked as they headed back outside.

"It's a long story. Maybe I can tell you next time?" She said, looking hopeful.

"I'll need to think about it first." Rin said. He'd never been given the freedom of choice before. It didn't feel as free as he'd always assumed it would feel. In fact he was compelled to just tell her that he'd go with her, even to the ends of the sky if that's where they were headed. But it would mean leaving his dad behind.

"Alright, I'll be waiting for your answer." She said and waved good-bye.

Both he and Yukio returned her smile and waved as well. He looked up towards the dragon shaped head of the ship. Wondering just what kind of adventures his father and Lyria had gone on, what kind of adventures he too could experience if he accepted her invitation.

A/N I had a lot of fun writing this. Did you like it? I'd really appreciate some feedback!