Jenny_Mythical_Witch and ginger300 both has really good ideas that linked into something I was gonna do so credit to those two 

EDIT: TW BLOOD

"Hey, Bats, why don't you bring Robin along for the mission? It'd be nice to get to know the little guy," Flash suggested. They'd been discussing a mission that wouldn't be too hard to pull off and it's always good to have an extra pair of hands. Plus, Robin had made a good impact on Gotham so they knew he was capable. Batman hummed and glanced over the details. They didn't know much about Robin and he preferred to keep it that way. No one other than himself and Alfred should know about Robin's dark side and this mission threatened that. "C'mon, we haven't seen him since our first meeting and it'd be nice to know a future colleague," Superman insisted.

"Hm. I'll run it by him."

"He seems like such a cute kid, it'd be nice to see another side of him," Wonder Woman commented. 

"You have no idea."

After mulling it over a few times, Batman told Robin about what the League members wanted and the naive boy agreed to it without even thinking of what could happen. He was a massive fan of the Justice League so he easily overlooked the glaring issue that he couldn't quite control himself if things got bad. Despite this, Batman accepted that he wanted to come and, after a short briefing on what they were going for, they went to meet with the League members. "Hey, little dude!" Flash greeted, grinning instantly at the sight of the small hero. Robin grinned back and gave the speedster a high five. 

"I almost forgot how cute you are," Black Canary cooed, pinching his chubby cheek. He batted her hand away softly with a small blush. 

"You ready to fight some crime with us?" Wonder Woman asked, silently squealing at how adorable the small boy was. Especially in his hero suit. He was like a kid dressing up for Halloween. "Yeah! But B said I have to stay with him the whole time n if I do good, next time we go on a mission together, I can pair up with one of you guys," Robin explained. Even his voice was adorable. As he talked he'd rock on his feet a little and he fiddled with his gloves mindlessly. They could tell he was a hyperactive kid by the way he spoke but they appreciated that he was doing his best to keep his attention on them. "If you're done fawning over the poor boy, we have more pressing matters," Batman announced, frowning at the group. He often wondered if the compliments would feed into the other side. He took hold of Robin's hand and led him to the invisible jet. "Bagsie pairing up with Rob first," Flash announced, running to the jet before any of them could argue against him.

Batman watched his protege carefully during the flight. He didn't want the younger to feel overwhelmed and flip out. Though it seemed he was very comfortable sitting in between him and Martian Manhunter. "Are you bald to be more aerodynamic or as a fashion statement because both are pretty cool?" Robin asked. 

"Robin," Batman warned.

"He's quite alright. I'd say it's a mixture of both," Martian Manhunter replied.

"Cool. Maybe I should shave my head," the boy mumbled.

"Absolutely not! If I even see a pair of clippers in your hands, I'll put a crucifix on your door," Batman cautioned. This wasn't the problem he thought he'd be dealing with when he brought Robin along on the mission but here he was. He supposed he should be grateful that this was the problem. "A crucifix?" Flash whispered to Black Canary. He didn't remember that in the parenting handbook. The blonde shrugged at him, clearly as lost as he was. "You wouldn't dare," Robin fired back. 

"I've done it before and so help me will I do it again," he snapped. The boy huffed playfully and turned his attention to the window. He'd never been this high before and he had the awful urge to skydive out for fun. Obviously, he'd probably die or something but he still thought about it. It'd be fun for five minutes. "So how are you liking school?" Wonder Woman asked Robin, knocking him out of his trance. 

"It's been fine. Though there's this one kid who's really cool, wears the inverted pentagram and everything so we're like best friends. Sometimes I think they don't know what it means but I'm not gonna tell them," he answered. 

"Isn't that Ace?" Batman asked.

"Yeah."

"What happened to Casey?"

"She started wearing a crucifix to school," he replied. 

"What's wrong with religious people?" Superman asked, slightly worried for the kid. Was Batman secretly against religious people? He didn't want Robin did grow up with such a stigma when he was supposed to be a hero who fought for justice for all. He seemed like a nice person too so everyone should have the ability to be friends with him. "Nothing is. It's a bit weird to bring that up, isn't it? Were you starting a joke up?" Robin gasped. "Did I ruin your joke?"

"No, you said you couldn't talk to the girl because she wore a crucifix-"

"Hey B what's that?" Robin asked, pointing out the window. They all looked out. 

"Shit."

Alarms. Falling. Shouting. Black.

The first thing Batman felt was the pain. His body ached as he tried to open his eyes. He couldn't remember much. There were spots of memory where he was looking at the sky. He remembered someone talking and then something being wrapped around his chest and forearms. There was crying for a split second in the beginning. So familiar was that crying that he could name it. Oh God. "Robin," Batman called, unable to shout like he had intended to. He didn't know where he was but he didn't care about that. He needed to know where his ward was right now. If things were bad, he knew what would happen. He needed to know Robin was still Robin. "I'm here B. Don't worry, I'm gonna get us out of this," the boy answered. That adorable voice didn't mask the undertone of what he was saying. Batman suddenly became very alert and shook his head. 

"No, we don't need that yet chum," he insisted. Robin shook his head. There was a large cut on his forehead and blood was trickling down the right side of his face. Batman suspected he wasn't much better himself but he didn't want to accept that they needed that side. Not yet at least. "I think we do. Everyone's in handcuffs and they're still hurt from the crash. If we have any hope of getting out of here then I'll have to bite the bullet," Robin said.

"What's he talking about?" Green Arrow asked. Batman wondered how long everyone else had been awake. He'd hate to think Robin the first one. He would've been so scared. Maybe that's why he thought he needed to turn to their last resort. "You're not doing that. You can't control yourself when you're like that," Batman reminded him. "You were so sick last time, you could hardly get out of bed. Don't put yourself through that again."

"That's only because I went too far. We don't have a choice B." He took the older's hand in his and gave a light squeeze. As much as he hated that he couldn't control himself, he was itching to go into his true demon form and wreak some havoc. "Batman we're out of the loop here. What's he talking about?" Black Canary stated, beginning to get uneasy. She didn't like how the boy was talking.

Not a moment after her question, Robin's body slumped forward and a substance like thick oil ran from his mouth to the floor. "What's wrong with him?" Wonder Woman shrieked. She was very sure Robin wasn't supposed to do that. Was that what his blood looked like? If so he should probably get checked out. The liquid bubbled and collected together to create a humanoid shape with the additional wings, horns, and claws. It clicked its neck before snapping its eyes open and looking around. "Ooo lookie here, we've been captured!" he announced.

"Who are you?" Superman asked defensively.

"That's Robin. He's a demon. Deal with it," Batman stated bluntly. He held his unconscious ward in his arms tightly. He didn't like the demon form. It wasn't the Robin he knew. The demon snapped his claws and their handcuffs popped off and the ropes around their ankles and forearms burned up without causing any damage to their persons. "You've done your job now. Back in your body," Batman ordered. Robin cackled. 

"Oh c'mon Batsy, I've not been out in so long! Not to mention that you're all still injured. How about I get you guys out of here then I go into my body?" He bent backward to face the other heroes. "It' a great idea ain't it?"

"Batman, you can control him right?" Green Arrow asked warily. The demon's smile turned sour and he growled frustratedly. He straightened up and looked around. They were in a prison cell without any natural light so maybe they were underground. That'd be fun. He walked over to the wall and punched through the stone. His hand his metal then dirt. So they were underground. "You're uhm you're very strong for your age... I think?" Flash commented in an attempt to make small talk. 

"Actually I'm very weak for a baby but thanks for the compliment. We're underground," he stated. He licked the dirt on his claws with his forked tongue. "Ooo not too deep either. Alright, ya layabouts let's get out of here. Someone pick up my body. If any of you bruise it, I'll fight you." The heroes gulped. "Kidding! And I thought Batsy took things too seriously."

Robin slipped through the prison bars and split into four smaller versions of himself to search their immediate area for any dangers. "Batman, you never told us he was a-a demon," Black Canary stated. Everyone was in shock. Robin was so cute and seemed so sweet yet he was this all along. Was it all just a cover-up? Then there was the thing of him having super strength and being able to split himself and God knows how much more he could do if he wanted. "It wasn't necessary," Batman replied. He held Robin's unconscious form in his arms with a sorrowful look. His poor boy. "Of course it was necessary! We're working with a demon! You're working with a demon!" Green Arrow interjected.

"Demon is an umbrella term! His parents couldn't have a child so they summoned an entity to give them one. They got Robin, a mixture of both human and demon," he explained. It was only the footnotes of the story but it would do for now. "Is he technically dead when he's out of his body?" Flash asked, lightly poking the body. Batman glared at him.

"I'm not in the mood to go over specifics."

"I suppose this would explain why I felt something odd about him," Martian Manhunter muttered.

"Are we all just going to ignore the fact that Robin is also a demon who by the sounds of it can't control himself in that demonic form?" Green Arrow exclaimed. The group looked at one another then shrugged. 

"Yeah pretty much," Flash replied.

"This is the reason we keep getting captured."

After a while and quite a few screams followed by cackles, Robin returned and reformed to his full demonic. He was holding a set of keys and- "Robin put down the gun we're not using guns," Batman ordered. He held it with a grin.

"But it looks so cool!" 

"No, put it down right now." The demon stomped his foot but released the gun anyway. He opened the door for them and surrendered the keys to Batman after getting a glare. "There's an elevator through here then there's an airplane hanger where we can steal a whole ass jet! Isn't that awesome?" Robin explained. He watched them nod nervously and rolled his eyes. "Urgh, it wouldn't kill you guys to have some fun. Speaking of, how 'bout I stay here to make sure nothing is going on and then you guys can go back to fix yourselves up?"

"No Robin. You're not staying in this form any longer. Back in your body." The demon growled at his mentor. 

"I don't want to."

"It's not a matter of wanting to. It's a matter of having to," Batman reminded him. A hiss of discontent was his reply as Robin defiantly stayed outside of his body. 

"Yeah? What're you gonna do to make me?" he snapped, his fangs growing. 

"Richard this isn't the time-"

"Any time is the best time for me! So you guys can get going whilst I have some good old demonic fun." 

"Richard don't-" The demon disappeared in a puff of smoke before he could get out another word. He tutted and glanced down at the body he was holding. He sighed noticing Robin's face had begun to grow pale. "Fine. If he's going to be a brat, he'll be treated like one."

"What? We can't just leave him here. What if he kills someone?" Superman argued. 

"He won't. He follows that rule at least. We'll follow his plan to get out of here then I'll just summon him home. Unfortunately, I require all of you to get enough energy to get him back to Gotham," Batman explained. "After that, you don't have to work with Robin and he won't work with you. I should've known this would be a disaster."

"Hey just because the kid is a little...off doesn't mean we don't want to see him again. All kids can be a little bratty it just so happens that when he's bratty he's a demon," Flash defended. 

"Speak for yourself! That kid is freaky as anything," Green Arrow argued. 

"I don't care what either of you think. Let's just get out of here," Batman snapped. 

Once they'd flown home, Alfred greeted them but he could tell something was going on. Robin was unconscious in Batman's arms but he wasn't worried. He looked angry. His teammates looked uncomfortable. "He didn't," he stated. 

"He did. The stupid boy decided he wanted anarchy so now I have to summon him back here. He's so grounded when he gets back," Batman answered. He handed the body in his arms to Alfred and rummaged through his draws to find some chalk and candles. This wasn't what he wanted to do today but here he was. "Don't call him stupid. You know he can hardly control himself when he's like that. I've told you before that you mustn't even let him leave his body," Alfred defended. The lad wasn't there to defend himself so he'd have to do it in his absence. 

"I didn't have a choice in the matter. Had we not been in the plane crash he wouldn't have felt the need to jump out. I'm this close to getting him exorcised or something," the billionaire muttered angrily. He took out the chalk and began drawing an inverted pentacle on the ground. 

"You shall do nothing of the sort. If you practiced with him being out of his body then we wouldn't have these problems," Alfred argued. "His other form is no different to a muscle. You need to train it."

"I don't want to train it. You've seen him when he's like that and afterward."

"Uhm, sorry to butt in here but suppressing a part of yourself can be harmful. When I don't let out my energy, I vibrate at work and can't concentrate," Flash butted in. 

"Wait so you haven't even tried to train that side of him? No wonder he can't be controlled! You didn't even try!" Green Arrow added. He couldn't really have anything against the kid if he truly couldn't control that side of himself. Batman didn't even try to help him control it. 

"Shut it. Just two hours ago you said you didn't want to see him again and now you're taking a sudden interest in my parenting?"

"You didn't tell us anything about Robin! How can you expect me to have a solid opinion if you never told us everything?" Green Arrow pointed out. 

There was a long pause as Batman finished the first part then set down the candles. He huffed as he went back to his drawer for a lighter. "I didn't want to tell you anything because obviously the word demon makes you think evil. He's not evil. He's the same as any other kid with a bit more of a liking for anarchy. He looks up to you for some reason I can't think of currently and if you didn't like him, it'd crush him to know something he couldn't help made you not like him."

"I can't say that we wouldn't have had our reservations towards the boy but we would've still given him a chance," Superman said. "You should've at least told us he wasn't completely human because what if something happened? What if he went into his demon form whilst you were knocked out still and we fought him?" The dark knight remained silent as he got out the lighter. 

"I'm trying to do what's best for him. I don't know how to deal with a normal child let alone a demonic one," he finally said. He took Robin's limp body from Alfred and laid him in the middle of the inverted pentacle. It was then when he noticed something that had certainly not been there beforehand. There was a burn mark in the shape of a crucifix. "None of you are wearing a cross right?" he asked though he knew that was a stupid question. They nodded. "What has that boy gotten himself into?" he muttered. One of the men, wherever they had once been, must've been wearing a cross. He needed to get Robin back home and quickly before one of them decided to try their hand at an exorcism. He moved to the outside of the chalk and lit all the candles. "All of you stand around here. He should be weak enough from fighting for us to have enough energy." They nodded and got to their places.

"Do we hold hands or anything?" Wonder Woman asked.

"Just concentrate on the circle and think of Robin. I know you don't have many memories of him but you should be enough with your brief encounters." They nodded and thought about when they met Robin that morning and on the jet. It was much better to think about than his demonic self. Though that was mostly unavoidable. "Richard Grayson, where ever you are or whatever you're doing, you come home right now. No ifs, buts or can I justs about it. Home. Now."

The chalk they were standing outside of lit up with a soft red glow despite the chalk itself being red. The flames from the candles grew and flickered softly. They watched them dance as a black smoke appeared inside the pentacle. Dark eyes appeared before Robin appeared in his full demon form. He looked beat up and tired, both most likely due to his fighting. He looked around in confusion and looked almost fearful of where he was. "Dickie, it's me. You need to go back in your body now," Batman called to him. He made his voice slightly softer than it had once been since Robin could gain the energy to break away and jump back to where ever he once was. 

"It'll hurt," the child replied. "And you're mad."

"I won't promise you won't have to face some sort of punishment-"

"Master Bruce," Alfred said in a warning tone. "Remember about your lack of training." The billionaire did his best not to roll his eyes. He felt like he was being told off as though he was a child. Parenting was even harder if both guardians didn't agree on what to do with the child. Still, he presumed Alfred knew best and relented. "-Okay, no punishment. Just go back in your body because the longer you stay out the worse you'll feel." Robin nodded and melted into the dark liquid he'd come from. He moved back into his body and after a few moments, his human eyes snapped open. The glowing died out and the flames on the candles were snuffed out by an invisible force. He groaned painfully thanks to his injuries from the crash and the reunion with his demonic form. Batman ran to him and helped him sit up, a small smile on his face. "Hey chum," he greeted. His previous frustrations over this melting away.

"Bruce?" Robin asked as tears bubbled at the corners of his eyes. He wiped them away with a balled-up fist forcing Wonder Woman and Black Canary to coo ever so quietly. "Are they mad?" 

"No, no one is mad. You tried to help and that's a good thing. Let's get you to bed, okay?" the older assured him. He scooped him up and Robin fell asleep instantaneously. 

"Aw, he's rather cute when he's all tuckered out," Superman commented. 

"You know who would like this kid? Wally. We should set up a play date," Flash suggested. "No crosses or salt."