So this is a year in the making (literally) and I'm glad to finally get it out there! It started with an idea I had about a SU/OP crossover and everything grew from there. Unfortunately, I couldn't squeeze in every detail about the world that I wanted to, so I'll have extra tidbits of fun facts at the end of each chapter.
The art was done by the super incredible 4annfals on tumblr, so go check her out and give her art some love! Seriously, she's been almost ridiculously patient with me. Thanks to ff being shite, I can't actually link the art here directly, but if you take out the spaces from this link then you should be able to see it: bit . ly / 2tt0yWX
Also a huge huge thank you to the best beta ever aka shishiswordsman, and LeafyxThiefy for helping this story get finished at all. I literally could not have done this without you, I can't thank you enough for all the help and support and brainstorming. You're the best!
This story has 5 chapters and I'll be posting one every week, so keep your eye out! And as always, enjoy! :)
Ace blew out a breath as he straightened up, looking out across the forest to where he could barely see the setting sun through the trees. He had been talking with Sabo about moving their treasure for a while now—their last spot had become too small to contain all of their stolen goods—and it was nice to know that it had finally been relocated somewhere more secure. Maybe they should split the stash up and disperse them to different locations, in case this spot was discovered as well.
Ace frowned, remembering how excited Luffy had been to discover where Ace went every day. The brat had been following Ace through the forest for months now, but Ace had never expected that the kid would actually manage to reach the Gray Terminal. He most certainly hadn't anticipated that Luffy's penchant for attracting trouble would land him in the hands of pirates within an hour of showing up.
Either way, their treasure was safe again, and Ace was sure that Luffy had cracked under the pirate's questioning by now. He was probably back with the bandits already, or wandering around the woods again trying to find them. Ace had to admit he felt a little bad for abandoning the kid, but anybody with a shred of common sense would cough up what they knew when up against real pirates. Luffy would be fine.
"ACE!" Sabo's voice reached him long before the boy himself appeared at the base of the tree.
"Sabo! Where've you been? Have the pirates gone to the old spot yet?"
Sabo looked up at Ace with wide eyes, gripping his pole tightly. "No, they couldn't possibly know where to go," he said, his low, urgent tone promptly capturing Ace's attention.
"...what do you mean?" he asked slowly. "There's no way Luffy hasn't told them by now, you saw how much of an open book he is."
"There hasn't been anybody in the forest, Ace. Luffy-" Sabo adjusted his too-short sleeves, a nervous habit that revealed just how unnerved Sabo was truly feeling at the moment. "He hasn't told them a thing!"
Ace could have sworn his heart actually skipped a beat.
"He's still with Porchemy, being tortured for information! I heard the Gray Terminal inhabitants talking about it in passing and I couldn't believe it either, but..." Suddenly, Sabo's urgency made perfect sense.
It'd been hours since Luffy was taken away, and Ace and Sabo had both heard plenty of stories about just what the pirates in the Pirate Cove were willing to do to get what they wanted. Luffy was annoying and loud even on a good day, but pair that with a stressed underling who wasn't getting the information they wanted...
"Ace! We need to go now, or Luffy is going to be killed!" Sabo stressed, his voice cutting through Ace's thoughts like a knife.
He nodded, grabbing his pole before racing off with Sabo back to the Gray Terminal.
They emerged from the forest in record time, and Ace relied entirely on Sabo to know where he was going. When they ended up veering away from the Pirate's Cove, Ace was momentarily confused before he realized that Porchemy had probably taken Luffy to a more remote location to avoid Bluejam's wrath. It was just one more sign of how dire the situation had become.
Ace's mind was running through a loop of 'why's, unable to understand how the weakling little kid that nearly got himself killed on a daily basis for no reason hadn't told the pirates a thing. Ace had been absolutely certain that Luffy would cough up the info after a mean look or two, and he'd come out of it a little shaken, but still in one piece.
It didn't make sense no matter how he looked at it, but Ace cleared his mind as a dilapidated shack came into view, and he prepared himself for the fight they were about to get into.
As expected, the Bluejam pirates did not go down easily, but with Sabo's help the two of them and Luffy managed to escape back into the safety of the woods. He now sat on a large tree root, attempting to repair his staff and coalesce his baffled thoughts. Ace couldn't help but glance at the kid with tears streaming down his cheeks as Sabo treated his wounds, unable to align the facts as they were with the truth as he saw it.
How could such a crybaby not crack even slightly after hours of painful torture?
Logically, Ace knew that Luffy must have been in a lot of pain, but eventually his sobbing grew to the point where Ace couldn't ignore it any more. "Will you shut up already?" he shouted irately. "You're so annoying! How long are you gonna keep crying like that? I hate weaklings like you who cry all the time!"
"Ace-" Sabo chided, but the sobs immediately stopped, surprising the both of them and stilling the words on his tongue.
Luffy's head dipped into a bow, hands clenched into fists and voice hitching dangerously. "Thank you, for- for saving m-me." The tears began to flow freely again, and Ace would have jumped forward to shake some sense into him if Sabo hadn't held him back.
"He's just trying to thank us Ace, cut him some slack." Sabo gave Ace a serious look.
Ace scoffed. "Either way, why didn't you just tell them what you knew? Those guys have killed women and children without a second thought, who did you think you were dealing with?"
"Because..." Luffy said quietly. "If I told them where the treasure was, I wouldn't be able to be your friend."
"That would have been better than dying. Why do you want to be my friend so bad that you would get yourself killed for it, anyways?"
"Because there isn't anybody else!" Luffy shouted. "I can't go back to Windmill Village and I hate those stupid mountain bandits! If I didn't follow you... I would be all alone!" Luffy shouted, bandaged hands clenching into fists at his sides. He wilted soon after, casting his eyes down to the dirt. "Being lonely is worse than getting hurt," he murmured.
The accuracy of that statement stopped Ace in his tracks. "What about your parents? Where are they?"
"Dunno. Gramps is the only family I have," Luffy said, and suddenly Ace found that he couldn't blame the kid any more. Somehow, Luffy had managed to dissipate all of Ace's anger with that single sentence. Ace knew all too well the pain of being completely and utterly alone, and he averted his gaze, unable to look into Luffy's pained eyes. Had Luffy experienced that very same feeling?
"You're not so lonely when I'm around?"
"Right."
"And you would be if I wasn't here?"
"Yeah."
"Then... you want me to live?" The question had slipped from Ace's lips before he'd gotten the chance to swallow it, and he wished that he could snatch those words back out of the air. He could feel Sabo's eyes darting between the two, obviously understanding the magnitude of this conversation, but Ace stubbornly ignored him, waiting to see how Luffy would respond to such an obviously out of place question.
"Of course!" The answer came so swiftly and surely that it left Ace no choice but to believe its sincerity. Even if it wasn't for that, Luffy was clearly the type to speak his mind regardless of what others expected of him. If he truly believed that he would never be able to have a friend if he said a word about the treasure... that was something Ace could almost believe. Only an idiot like Luffy would think like that, but maybe Luffy could an exception to the rule.
"Okay." Ace turned away, the gravity of the conversation pulling too heavily on him. "I still hate spoiled brats like you, though."
That riled Luffy up, of course, and he jumped off of the tree root directly into Ace's space. "I'm not spoiled! I'm strong!" Luffy declared, and god if this kid didn't push all of Ace's buttons the wrong way.
"Strong? What do you mean strong? You can't even stop crying for two minutes!" he accused, getting right back in Luffy's face.
"Have you ever been punched with a spiked glove? It hurt! I won't cry at all when I'm ten like you! And we'll both be way stronger than you are now too!"
"Idiot, I didn't- wait, we?" Ace stumbled over his words once his brain caught up with what Luffy had said.
Luffy's lips immediately puckered into a face that couldn't more clearly signify that he was lying. Ace wondered how the hell this kid had managed to live so long with such a horrible poker face.
"I. I said I."
"No, you said 'we'. What do you mean 'we'?"
"I don't mean anything!"
"So you admit that you did say we!"
"Luffy," Sabo intervened. Luffy turned to him with wide, curious eyes, and Sabo stepped between Luffy and Ace to prevent any further conflict. "You said you want to be our friend, right?"
"Right."
"And friends don't lie to each other or keep important things secret, right?"
"Right."
Sabo waited a moment for Luffy to make the connection, but it seemed it would take some further prodding. No wonder Porchemy had such a hard time trying to get any information out of him. "If you want to be our friend, you can't keep secrets from us."
"Oh." Luffy seemed to consider this for a moment before averting his eyes. "But gramps doesn't like it, he says it's cheating!" he protested. "He always says that we should never fuse, but then he leaves and it's less lonely when we're together!" His entire demeanor screamed of someone who had been caught with their hands red handed, but Ace still had no idea what Luffy was going on about.
"Fusion?" he asked, bewildered by the sudden change in conversation. "Do you have a brother or something?"
"Your gramps told you to never fuse?" Sabo questioned, and Ace's gaze flickered to him, looking for an explanation but finding none.
Luffy nodded. "Yeah, so that's why I can't tell you that I'm a fusion, or else gramps will get mad!"
Silence, and then- "Crap! No, wait, I didn't say anything! You didn't hear that! Don't tell gramps I told you!" Luffy started backpedalling furiously.
Sabo only laughed, "We don't care if you're a fusion, Luffy."
This gave Luffy pause, and he cocked his head suspiciously. "You don't?"
"No," affirmed Sabo, placing his hands on Luffy's shoulders. "Luffy, don't let anyone, not even gramps, ever make you feel like you don't deserve or shouldn't have what you want. Okay?"
Luffy nodded, and Ace finally found his voice to speak up, the initial surprise from the reveal fading. "But you only have one gem. How can you be a fusion with only one gem, aren't they supposed to have two?"
Ace admittedly did not have much knowledge about fusions and how they worked, but it was common knowledge that a fusion was stronger than its two parts, and there was one gem for each person involved. Trust that shitty geezer to plant the thought in Luffy's mind that fusion was cheating.
"Stupid Ace, the gems are both in the same spot," Luffy said, rolling his eyes as if that should be obvious.
"Who're you calling stupid, idiot?" Ace shouted, butting foreheads with Luffy yet again.
"Alright, that's enough!" Sabo interrupted, shoving the two of them apart again. "Now that that's out of the way, I have a problem, so I need you both to hear me out."
"A problem?" Luffy echoed, anger forgotten with the wind.
"Right." Sabo nodded. "Before today, I usually slept in the forest 'cause it's safer and away from the rest of the Gray Terminal. After tonight the pirates will be looking for all three of us though. What would happen if Bluejam attacked me in the night while I was sleeping?"
"You'd die."
"Right." Sabo pulled them into a huddle. "So here's that I'm thinking—"
A few months later, Ace was standing alone at the top of the treehouse they had built, with nothing but the cold night sky to keep him company. The stars glinted far up above, seemingly weightless against an inky backdrop, but his chest was heavy after another trip back from Low Town. Cruel laughter echoed in his ears, and Ace turned his head away, gripping the wooden railing so tightly it splintered and left fresh new stinging cuts on the palm of his hand.
He didn't know why he went back. Didn't know why he'd even started going in the first place when the outcome never, ever changed. He hated hearing their drunken thoughts about how the son of Gold Roger could never be anything more than trash, but some wandering part of him couldn't resist the temptation. He never wanted to be the son of the Pirate King; didn't ask to spend what would likely be the rest of his life cursing his father's name. Ace wished more than anything that he could have been born to normal parents so that the blood of a demon wouldn't be running through his veins, but here he was.
Lost in his self-deprecating spiral of thoughts, Ace failed to notice the quiet sound of footsteps approaching from behind.
"Ace?"
Ace jumped at the sleepy voice, whirling around to find Luffy standing in front of him, half awake with a ratty blanket spilling from his shoulders. Usually when Ace got in this kind of mood he would go hunting and take out his frustration on some animals, but with his brothers sleeping in front of the door, he hadn't wanted to risk them waking up and asking questions. A lot of good that plan had done him.
"Go back to bed, Luffy. I'll be there in a minute," he said, trying to keep his twisted emotions from bleeding into his voice.
Luffy, of course, acted like he hadn't heard a word Ace said. Instead, Ace was surprised by a sudden warmth as Luffy's blanket-swathed arms wrapped him in a tight hug. Ace immediately stiffened, mentally cursing Luffy's inability to listen, but no matter how gently he tried to pried the imposing arms away, Luffy refused to budge. Ace soon gave up, begrudgingly accepting the comforting warmth.
"Why are you sad, Ace?"
Ace jolted, not expecting the sudden blunt question. "I'm not."
"Makino always said that the people who are always alone are always the saddest." Luffy's head tilted up so he could give Ace a small grin. "But I'm here now, so you don't have to be alone and sad, okay?"
Although they were muffled by the blanket and Ace's clothing, Luffy's words were no less powerful, stealing away any response Ace might have given. Luffy always had been exceedingly perceptive when it came to what the people he held dear needed, like a hug or some kind words at the exact right time. It was just another part of his brother that Ace hadn't even begun to understand, but he went with it. Over the past few months he'd found out that doing so was ultimately much easier in the long run.
Something tight drained from Ace's chest, and the empty space left behind was flooded with warmth. The pain he'd felt so sharply diminished within the aura of the happy little boy currently squeezing the life out of him. It was impossible to be upset around Luffy; the boy exuded happiness in a way that was infectious to everyone near him.
"Yeah," Ace said softly, a small smile unknowingly making its way to his face as he turned into the embrace. "I guess you're right."
Ace had never fused before, but if he were to guess what it would feel like, he would think of something like this. Ace's cheeks flushed at the sudden intimate thought. Ace had never cared about his gem beyond the strength it gave him; never cared about fusion or even getting close enough to another person for fusion to even be possible.
Why would anybody willingly fuse with the son of a demon?
Fusion was the ultimate show of trust and acceptance between two people, and therefore something Ace could never have.
Ace stepped out of Luffy's embrace, ignoring the protests it earned as he climbed back down the ladder and into the treehouse. Sabo still lay sound asleep on one of the mats, wrapped tightly around a pillow for protection from the cool night air. Ace paused, just looking at his closest and only friend for the past five years. Sabo's chest slowly rose and fell evenly, deep asleep.
Sabo had been the first person Ace had ever dared to let stick around. They had always operated on a don't-ask-don't-tell basis, and Ace had assumed that it was a mutual agreement between the two of them. Ace thought of the few times Sabo had tried opening up to him in the past, and of the numerous times Ace had held him at arm's length in return.
The tight feeling returned to his chest, and Ace automatically turned to leave once more, only to find himself blocked by Luffy. Again.
"Ace? Wh's wrong?" Luffy swayed slightly as he stood, as though his body was physically weighed down by the boundless dreams it could be having, but the concern in his eyes was genuine.
"...nothing," Ace found himself saying, taking Luffy by the shoulders and leading the boy back to his mat. "'m just tired, that's all."
Luffy gave little protest to being herded back to bed, fading as soon as his head hit the pillow. His arms opened up, inviting Ace into a cocoon of warmth and safety.
Already Ace could feel himself pulling away, a refusal perched on his lips, but then Sabo mumbled something in his sleep, and Ace was reminded of the tightness he'd felt.
Ace imagined his life after five years of treating Luffy the same way he had Sabo. Luffy would no longer offer those bright smiles to Ace, no longer try to drag Ace along on adventures or into town to eat ramen or get into fights, and Ace's heart ached. For all of his attempts to be left alone, Ace knew that he had never truly wanted the isolation that he pushed so hard for.
Just this once, Ace let himself give into the temptation Luffy offered, climbing under the thin blanket and laying there until the quiet breathing of his two brothers lulled him into a deep, dreamless sleep.
From that day on, Ace made more of an effort to not close himself off from Sabo and Luffy. As much as he didn't want to, eventually the three of them would have to part ways, and Ace didn't want to have any lingering regrets.
Sabo, of course, had picked up that something had changed, but he said nothing, much to Ace's relief. Luffy, however, was too thrilled by Ace's newfound willingness to go along with his whims to question the reasons why.
Ace found himself being dragged into even more mischief than before, if that was even possible. Every trip into town had turned into the three of them gasping for breath through peals of laughter as they ran from adults who'd experienced Luffy's special brand of chaos first hand.
At some point, their mats in the treehouse had all migrated next to each other to form a circle, and there was talk of finding better ones in preparation for winter. The number of solo trips Ace took into town began to slow before stopping altogether, his days too filled with adventure for any other nighttime escapades.
And finally, Ace was happy.
The three of them were sitting around a campfire now, enjoying a fresh meal of roasted crocodile. The meal was Sabo's treat, a result of a double dare from Ace and Luffy that he wouldn't jump into the river to catch one in the middle of winter.
Once their stomachs were sufficiently full, Ace was content to listen to Luffy's telling of how he would singlehandedly defeat the tiger lord. When Ace and Sabo didn't seem particularly impressed by the declaration, he then went into more detail of exactly how the fight would go down, and Ace and Sabo settled down to see just how crazy Luffy's story would get.
The night was full of laughter as they all traded stories, leaving Luffy slack jawed at all the trouble Ace and Sabo had gotten into long before he came around. At some point, Sabo left to get "something special" from the treehouse, deserting Ace to the task of defending their food from wild animals — Luffy included.
The boy in question lay on his stomach, legs swinging in the air as he studied Ace curiously.
Ace pretended to tend to the fire for a minute despite the fact they both knew it was practically self-sufficient in Ace's presence. Ace liked to believe that he'd gotten better with staying calm and controlling his temper, but he grew more restless with each passing second. FInally, he snapped. "What are you looking at?"
"Ace," Luffy beamed, kicking his legs some more and burying his head in his arms as if he had discovered an amazing secret.
"Well, duh," Ace sighed, wondering just what plot Luffy was brewing up now. "I meant why are you looking at me?"
"You're not sad any more!" Luffy enthused, hopping up and bounding over to Ace excitedly. Ace automatically shifted to protect what was left of the food.
"So?" Ace's cheeks heated. It was the first time either of them had mentioned Ace's change out loud. Ace figured Sabo must have said something to Luffy to keep him quiet about it, but then again, Luffy wasn't the best at holding back whatever thought came to mind.
"We should fuse!"
Ace's mind short circuited.
"What?" He was almost certain that he'd misheard Luffy somehow, despite the fact that Luffy was standing directly in front of Ace and speaking louder than was necessary, as per usual. "I mean- what?"
"Fuse with me!" Luffy repeated, rolling his eyes as if he couldn't believe that he needed to explain this to Ace. "You know, dancing and then there's this big light and a whoosh! and then you're somebody else! Kinda."
"I know what fusion is, idiot," Ace scoffed, cuffing Luffy's head in irritation.
"Then let's do it!" The boy didn't seem at all deterred, grabbing Ace and whirling him around. Ace had to pry Luffy's hands away to get him to stop.
"Luffy, you can't just say 'hey, let's fuse!' out of nowhere!"
Luffy cocked his head, brows furrowing. "Why not?"
"Because... you just can't. That's now how it works."
That only served to confuse Luffy even more. "But that's how Lemon and Spinel do it. Though they don't really need to dance any more. They just like to."
"Well that's- I… don't know how to do it," Ace admitted, crossing his arms and turning away so he wouldn't have to look at Luffy. He'd never expected to get backed into a corner by Luffy of all people. "I've never fused before. With anybody."
"Never?"
"No."
"Not even with Sabo?"
"NO!"
Luffy was unperturbed by Ace's shouting, instead breaking out into a grin against all of Ace's expectations.
"Then that means I get to be Ace's first!" He laughed merrily, looking so thrilled at the prospect that Ace couldn't even bring himself to feel annoyed by his sunny enthusiasm. "Fusing's easy! There's no 'way' to do it really, but dancing is fun so I like doing that!"
Ace had no way to respond to that and allowed Luffy to drag him over to a clear area off to the side. He felt unbearably awkward at first just standing there swaying from side to side, but like always, Ace eventually found himself being drawn into Luffy's aura. It was impossible to feel negatively around Luffy—the kid had no sense of shame and not a single mean bone in his body.
At some point a music box appeared, though where Luffy had gotten it and how he'd managed to keep it hidden for so long was an absolute mystery to Ace. He didn't question it though, instead listening to the merry melody it twinkled.
The only problem was, the music kept cutting out as a result of its shoddy quality and needed to be constantly reset in order to keep playing. It wasn't long until it turned into a competition between the two, as most things did nowadays. Whoever was closest to the music box when the music ended would have to reset it, so those precious 30 seconds before the end of the song were spent with the two of them grappling and spinning around in a furious attempt to not be caught closer.
Ace was pretty sure that he was winning even though neither of them were keeping count. He didn't notice the warmth spreading from his chest all the way out to the tips of his fingers as he wrestled with Luffy, too caught up in the fun of their game to notice much else.
A bright light that enveloped the both of them, and suddenly, Clinohumite stumbled at the sudden lack of counterweight, arms flailing outwards to catch their balance. When the world stopped tilting, they froze, eyes scrolling down to find unfamiliar clothing and a strangely colored gem on their chest. It was bright orange, and the way it reflected the light of the campfire gave off the appearance that the gem itself was made of flames. A hand ghosted over their back where they knew the other gem gem was, right between the shoulder blades.
"Woah," they breathed, hands clapping over their mouth in surprise at their voice.
"Did I- We're..?" Clinohumite turned around as if they could examine their entire body that way, a laugh escaping them at the feeling of it.
"We did! I can't believe it, it's so- this is what it's like?" Heat radiated from their body in waves, eyes bright and full of energy. It felt good to be alive. They stretched their muscles, enjoying the feeling and measuring the strength that lie within them.
Crack.
Clinohumite whirled around to see a shocked Sabo staring at them, an armful of sticks and what appeared to be a bag of marshmallows in his arms. Clinohumite froze, their form wavering until it split in two.
Luffy and Ace fell apart, and Ace coughed as he swallowed a mouthful of mud. He sat up in a daze, the ghost of something still echoing through his mind and body.
"Ace!" Luffy joyously tackled Ace, sending them both sprawling into the dirt again. "I told you, didn't I?" Luffy beamed, looking so pleased that Ace couldn't help but ruffle his hair.
"Yeah, you did."
"What is going on here?" Sabo's voice brought Ace back to reality, his eyes snapping to where the blond still stood, staring at them in shock. Ace pushed Luffy off of him, suddenly nervous as to what Sabo's reaction would be. Would he be offended? Disgusted? Angry that Ace had fused with the boy they'd only know for a couple months when Ace and Sabo had been each other's only friend for the past five years?
Whatever it was, his fears proved unfounded.
"That was amazing!" Sabo exclaimed, tossing aside his armful and closing the distance between them. Questions poured from him like a river. "How did you do it? I've never seen a fusion before! What was it like? What gem do you guys have? Was it like being two people in one body?"
Ace was admittedly relieved when Luffy's stomach rumbled loudly, putting a stop to Sabo's barrage of questions. "Food now, questions later!" Luffy demanded, bounding towards the forgotten snacks. Sabo rolled his eyes as Ace snorted out a laugh. The two of them shared a look, and Sabo gave Ace a small smile.
"We'd better do something before he makes himself sick."
"Yeah." Ace shuffled nervously, stiffening when a pair of arms wrapped gingerly around his shoulders. Ace couldn't remember Sabo ever hugging him before.
"I'm happy for you," the blond whispered before pulling away and going after Luffy, shouting that the marshmallows were expensive and that they needed to share. His words fell on deaf ears.
Ace stood there for a few more moments, a lightness floating in his chest as he watched his brothers get into a scuffle over the now half-empty bag of sugary puffs. Ace's feet carried him to them like a magnet, unaware of the small smile that had settled on his lips.
It was nice, not being so alone.
Fun facts!
-Everybody in this universe is born with a gem somewhere on their body, and have all the abilities that a gem from Steven Universe would possess.
-Devil fruit abilities from OP canon are simply that person's gem-specific, completely unique specialty.
-Ace's gem is citrine and is located on his back, between the shoulder blades
-Sabo's gem is orthoclase, on the back of his left hand. His family had it engraved with their crest when he was born, so he wears gloves to cover it. He eventually has it re-engraved to look like a sun.
-Luffy is a fusion of star lemon quartz and red spinel, making Luffy's gem a fire opal. Both of their gems are located on their chest over their heart.
-Clinohumite has 4 arms and 4 eyes.