Everyone has a device, a small box with a tiny lightbulb inside to show the wellbeing of your soulmate. Dim means they're hurt or sick, while a bright light shows that they're healthy.

Ace didn't mind seeing either, since both told him his soulmate was alive and kicking. The only thing he never thought to see, was the absence of that beautiful small light.

(A/N: EVERYTHING WILL BE ALRIGHT, I SWEAR!)

Soulmate-AU
Temporary Character Death
Hurt/Comfort

Seeing he was done with his mission he was simply resting in bed in the inn he was renting in, planning to take a nap before starting the track home. No matter how much he just wanted to leave right now, it wouldn't do to just leave very excited, only to fall of striker from a sleep attack, so small nap before it was.

After a minute, he took a small box from his pocket and held it close to his heart before opening it and smiling. It was a very small rectangular box in the exact shade of Marco's flames, inside was his light. Marco's little light of life as Ace called it.

He watched it as it illuminated the darker room in a blue-ish hue, indicating that Marco was very alive and kicking, he smiled brightly at it as he hugged it close, turning onto his side and placing it down next to him, but never closing it as he watched it.

Whenever he was separated from Marco, he would watch this light whenever he had free time. The other, or himself, could be on a mission, or could simply have had a day of a lot of commander's work and having been holed up inside not wanting to be bothered. No matter if the man was actually close by or not, seeing the little light shine brightly always cheered him up and calmed his mind when he couldn't actually be with the man himself.

Even before he had met The Phoenix, when he was still small and sleeping with Sabo and Luffy in their tree house, he would –in secret of course– take the little box and look at the light when he felt down or whenever he just had the urge to do so. Especially if he had just been in a fight with people that said he should have never been born, he would sneak out or hide in a corner so the others wouldn't see, and would take the little box and open it, watching the light burn brightly. It was his soulmate. The only person in the world that won't... shouldn't... care who he was, a person that would love him for who he was, no matter his demon's blood. Even if he didn't yet know who it was, knowing this person was alive somewhere was enough to brighten him up and momentarily forget that besides the person behind the light, everyone wanted him dead.

So here he was, simply watching the bright light with a fond smile, caressing it with a single finger every now and then. When he was almost asleep the light started flickering, and while it did shake him out of his peaceful sleep, he wasn't too worried. The ship was probably attacked by some rookie crew or Marines upholding justice who were brave enough to try and face them.

He snorted as he saw it flicker a few times in a row, the light getting a bit dimmer before picking up to its usual brightness. Marco was probably having fun scaring the shit out of whoever attacked him. Letting himself get shot or stabbed, once he deemed the weapons weren't sea stone, and then smirking at the look of horror then the other noticed Marco didn't even flinch and healed seconds later. Their small moment of victory ruined before it even began.

When he didn't know the man, he had thought his light was broken at moments. No one healed from a sickness or wound this quick, but it never stopped worrying him if he had looked at it and seen it flicker. The Phoenix had profusely apologized to Ace and pulled him into a hug when he had told the man he had worried a lot as a kid... as a teen... when the light would flicker. Not knowing if his soulmate was actually okay, even if the light was bright, or if his device was simply broken. Marco had spent the whole day pampering Ace, telling him he didn't know the light would dim for the brief moment that he got a wound and made sure to reassure that he was very much alive, and in love, with Ace.

Now, he was used to the flickering, he didn't see it as often anymore since he was now often involved in the fights himself, being on the same ship, and you couldn't really watch your soulmate device in the middle of a battle.

Either way! While being a bit more awake he watched the small flickers, some would even fool you in thinking it was your own blinking that made the light seem dim for a moment, that's how quick it was sometimes bright again. He looked away momentarily towards his window when there was a sound when suddenly the room was drenched in full darkness, "huh?", had he knocked against the lid?

Turning back, he already had a hand reaching out to open the little box again, he wasn't done watching it just yet. But breath caught in his throat as he saw the box was open. "What?"
He sat up straight and took the box in his hand, turning on the little nightlight in the same moment. The little lightbulb... it was... off? No... that couldn't be. A light that was off meant your soulmate was dead, no longer in this words, 6 feet under, not- not touchable anymore.

Ace gave a weary laugh, "haha, Marco, what are you doing birdy, postponing your healing, just heal pineapple.", but the light stayed out. He put a hand over it and squinted at it to search for the slightest bit of light so he could just call it dimmed and not... not off. "C-c'mon Marco..."

Seconds passed and the light didn't go back on, he started panicking. Closing and opening the box, wishing each time that he was dreaming and the blue light would return. But with every opening that the room stayed dark, his breath and heartrate was picking up. Until... he could see the colour fading from the box. "No, no, no, no, no, no, no, no!" He desperately touches, chased, over the beautiful blue colour of the bow that was turning black, turning the box into a plain... box...

Tears started rolling down his cheek as he kept chanting in denial, denial that was getting louder and louder. He started screaming at the box for Marco to stop joking and heal himself, to not scare him like this, not when he couldn't even go to check on the man. "You promised Marco, you promised you wouldn't stay hurt for longer than necessary, knowing I can see it. You promised me that they I told you I had been scared before, so why, why are you scaring me again Marco! HEAL!"

Of course, a reply never came and the blue kept fading, leaving nothing but that ugly, colourless black. And when the last blue disappeared from under his finger, he screamed. He screamed his heart out and trashed around, screaming, cursing, yells of denial starting up again, yells that he hated the other for joking like this, only to apologize profusely to the little box the same moment, that he loved the man and could never hate him.

He heard the rushing of steps coming to his room, probably the owners of the inn, but he didn't care, his only focus was on the box and getting in control of his raging breaths. His lungs heart, his head hurt, his heart hurt. He couldn't breathe. "Marco-Marco-Marco, don't leave me, don't leave me, please, please", the blond couldn't be dead. He was a phoenix. Immortal and beautiful. They would stay together for eternity, they promised each other their life. So why, "WHY IS YOUR LIGHT OUT MARCO!"

The second he heard the door open was the moment he collapsed in on himself. He laid on the ground in a fetal position, clutching the box in his hand as he also clutched at his chest, desperately trying to breathe as he was choking on air, tears still streaming out of his eyes as it was sinking in that he would return home later, to a home without a soulmate waiting for him. He was alone now.

When he woke up his eyes hurt, he felt... empty... He was laying in the bed, even though he knew he had passed out in the ground. Turning his head, he noticed a glass of water and some pills next to it on the nightstand, the owner had probably called the local doctor to have him checked out. Deeming him 'okay' and putting him to bed.

He put an arm over his eyes as he started weeping again, sobs racking though his body as he remembered, remembered that he was alone. His soulmate, Marco, was no more. Had died, had perished, while he hadn't even been there, hadn't been next to him in his final moments. Had died, and he hadn't even seen the very last flicker of his light. He cried and cried for hours as the black box on his nightstand mocked him now.

Only when his tears had long dried up, no new ones forming again, was he finally able to pull himself together... Or well... pulling himself together was a big word. He was a mess, he looked like a mess he felt like a mess... he felt empty...

But... why hadn't his family called him yet? Shouldn't they... shouldn't they inform him of Marco's passing? The only thing he could think of is that they didn't want for him to freak out while away from home, that they would wait to tell him until he was back but... he had the light. Everyone had the light. The others knew he liked watching it, should know that he would check up on the state of Marco's wellbeing at every moment he could while away, so why aren't they calling him?

A thought went through his head, "no!", he shot up, got his belongings and ran out of the room, throwing some money at the owner of the inn and running out, ignoring the questions if he was fine. He ran the whole way to the docks and hopped onto striker with the speed of light and making his way home, they- the others may be planning Marco's funeral. They never waited long to hold one if needed, a body wasn't something that they could keep... fresh … for long at sea, especially not in the hot climate they were in now. And they couldn't risk any illness or infection to spread from the one who died, so the funeral, the last goodbye was often the same day or the day after.

It would take him longer than a day to get to the Moby and he had no idea how much time had passed since the light had flickered out. He couldn't-, tears welled up again and made his vision blurry, he couldn't miss his soulmates funeral. He HAD to at least be there for that. He wanted to see that stupidly handsome pineapple face again, kiss those full lips one more time even if they would be cold and unmoving, he wanted to weave fingers through those golden locks one last time, he had to engrave those feelings into his soul one last time before they send him out to sea. He had to make it back, he had to!

15 hours and 43 minutes. That's the time it took him to get Moby in his sights. He doesn't know how he did it, how he shaved more then 10 hours of his travel time. It may have something to do with the burning pain in his legs as his flames flickered behind him, desperately clinging to life as Ace kept pushing them out far past his limits. It may have to do with the burns he sported on his calves, his body literally not being able to take his past hours of usage of fruit, even if he should be the flames itself and it should have been impossible to get hurt. There was apparently a limit.

But he didn't care, he didn't care and pushed on until he was right next to the ship, letting striker hit the side of the boat as he hadn't bothered to brake before jumping off and onto the deck.

It was silent for a fraction of a second before people started smiling and cheering for his return, coming to pat him on the shoulders. He was confused, why were they smiling? How could they be smiling? They should all be devasted at the loss, the loss of the first commander, the loss of a brother, the loss of their friend. Even Pops welcomed him back with a smile when he should have been weeping for his lost son.

He snapped when the old man laughed at his messy appearance, telling him his hair was almost as spikey as Marco's now.

"WHY ARE YOU LAUGHING!" he screamed to his captain at the top of his lungs.

The deck was silent in an instant, everyone staring at Ace in shock at the outburst.

"WHY ARE ALL OF YOU SMILING?!" He scanned the deck as his eyes were starting to get moist very quickly, but fury was pouring out quicker than the tears.

"WHY! WHY DO YOU ALL LOOK HAPPY!?"

"Son... What's wrong? Did something happen boy?", The voice was so gentle, so caring, so concerned for him. For his wellbeing. HIS! He was alive! He wasn't the one that had passed!

He was sure he would have been burning the deck if he hadn't exhausted his fruit. "Did something happen?" he mimicked in a whisper of unbelieve, voice picking up as he repeated it and added to is, "Is something wrong? Wrong... EVERYTHING IS WRONG! MARCO IS- MARCO IS D-"

"What's with me-yoi?"

His words cut off as he choked on his breath at the voice behind him. Slowly turning around he came face to face with the first commander walking towards him, stopping an arm's reach away from him. "W-what?"

A distinctively arched eyebrow rose a bit, confusion and concern visible on his face, "What what-yoi?"

Was his mind playing tricks on him now, life couldn't be that cruel right? He was still the demon's child though... maybe life was this cruel to him...

He took a trembling step forward and reached out a hand, putting it on Marco's cheek. He could touch him. He was warm, he was there. His soulmate, the love of his live, his everything, was in front of him, looking very concerned at him, concern that was growing with every second.

"M-Marco?" he couldn't even understand himself with how he chocked that out, but the other did, he always understood him.

"Yes? I'm here. What's wrong Ace? Are you okay? Did you hurt yourself on your mission? You're back a lot earlier than expected." the man now scratched his neck and looked at him sheepishly, "I was making your favourite dessert with Thatch as a welcome back snack... it still needs a few hours in the oven though..."

That's it... he laughed a broken laugh and fell to his knees, sobs wracking through him as tears fell to the deck. Marco was next to him in an instant, kneeling down and inspecting his whole being for wounds, gasping as he saw the burns on his calves and calling for the nurses. He felt how those big hands he loved so much grabbed his face and wiped with thumbs over his cheeks. His face was lifted so he was looking into blue eyes, blue eyes he had thought he wouldn't see the shine in again.

"Ace, love. What happened? How are you burned? Did you run into enemies on your way back? Did they get seastone on you?-yoi"

He didn't react and instead a sob mixed with a laugh escaped him again as he pounced onto the other, throwing his whole being into the other and grabbing around his neck. His hands were clutching at his clothes as he cried into his neck, chanting the other's name.

He ignored every single thing that was said to him, done to him. As people talked to him, no matter if Marco or not, no matter if they had started to treat his wounds, no matter when he was picked up and carried off. He just clutched to Marco for dear life, not daring to let go in fear that this was just a dream. That he would wake up on striker, passed out, having missed his funeral, or having passed out, maybe drowning in the sea by now... not that that would be a bad thing... If Marco was really dead, he wouldn't want to go on anyway.

Was it his overwhelming emotions, or his stupid Narcolepsy, he didn't know, but he did know that he passed out. But that he passed out surrounded in the arms he always wanted to be in.

He once again woke up in pain, but not only his eyes, no, his whole body hurt and he groaned.

"Ace-yoi?"

Eyes shot open and turned to the voice, sitting next to him, holding his hand, was Marco. Still looking very concerned at him.

"Are you okay now? Are you feeling better? The nurses have treated you ca-"

"Marco!" He cried out and scrambled out of bed before Marco could stop him, not caring as pain shot through his legs, and he jumped the other, sitting on his lap as he hugged him.

Marco embraced him, still very concerned and very confused.

"Ace, can you talk to me? Please. What's wrong, I'm worried about you."

A shaky laugh left him, Marco was worried about him, him. When he was the one that was supposed to be- to be d-d-ead.

Leaning back, not afraid that he would fall, Marco had him now, he reached into his pocket with quivering hands, pulling out the small box. It was still as black as the night and when he opened it, no light appeared.

"That- Ace? Is that?"

"I-it's your-your light of life. M-my proof that my soulmate is a-alive."

The blond was silent and looked the box over before reaching into his own pocket, pulling out his own small box, only this one being bright orange. Opening it, it showed an orange light. Yes, it was dimmer than usual and that was normal, Ace was hurt, physically and mentally, but it was on, there was light coming of indicating Ace was alive, while... while the one that should show his live int Ace's hands was... was off?

"How?"

"I-I don't know, I don't know!" Tears were falling again, "Y-yesterday, I think it was yesterday, I don't know, I passed out for a while... I had finished my mission and was resting in the in. You know, just so I could return home without fearing I would have a sleep attack."

The blond simply nodded at that, swiping away some hair from Ace's face as he let him tell his story.

"I was watching your light, like I always do before bed when we're apart."

Once again, he nodded, he knows his lover liked to watch the light, and he had to admit that he also frequently checked on Ace's whenever he was on a mission.

"It... it started flickering. I-I laughed at it, because, because I thought you were in a fight, teasing your enemies." His breath started picking up a bit and Marco tried to calm him by rubbing his leg, not wanting to interrupt the story but also to comfort the other, "I- it went on for a while and then there was a noise outside. I-I looked away and- and your light went out! The room, the room was suddenly dark Marco!" he sobbed out as he buried his head in Marco's neck, "It-It was dark, fully dark, not-not even the smallest spark of light coming off and-and it didn't come back. Didn't become bright again as always even when minutes passed, no matter how many times I closed and opened the box again. And-and then, then!" trembles were racking through him, the wet stain on Marco's purple shirt becoming larger by the second, "The colour started to disappear. Y-your beautiful blue, it-it started turning black. I- I tried to stop it, I-I... it kept disappearing under my hands! I- I THOUGHT YOU WERE DEAD!"

He fully broke down in Marco's lap. The blond couldn't believe what he was hearing. He wasn't dead. He was very much alive right now, breathing and moving around. Why... why did his light go out.

Rocking Ace in his lap, rubbing over his back and kissing him wherever he could reach, Marco whispered words of reassurance and love that he was okay, that they were both okay. But simultaneously he was thinking about the whole situation. How could the light die? They only went out if the other died. Some people said the batter of life was emptied out. But it's not like the box contained an actual battery, it couldn't just die out, it wasn't something that should be able to malfunction like that, the 'battery' couldn't just bug out or something...

Like Ace said, he did have a fight, two days ago now they were attacked around noon but nothing they couldn't handle. And like Ace said, he did have some fun teasing the others, letting himself be hit as they shot at hi- his eyes suddenly widened, it couldn't be!

During the fight, even after the other party was losing at a very, very fast rate, their attacks being useless again him and all of the other members, -The one who challenged them were just plain weak-, the captain had suddenly pulled out their 'ultimate weapon!'. It was essentially a big gun, smaller than a canon, but had the size of the bullets were about the size of a small cannonball that fit into your hand.

They had shot it at Marco, saying the seller had promised them it could take out 'anyone'! But well, he was a magical flying bird on fire that could heal from any wound, so tough luck with that when the bullet wasn't even seastone.

Sensing it wasn't seastone, Marco had let himself be hit. It had hit him good. While he would heal, he had felt the sting of pain as it fully tore through him. Entering his chest at the front and leaving a big exit hole on his back. The areas it had past were however instantly covered in blue flames, healing the damage away. But... It had passed through his heart. And while it hadn't bothered him in the slightest, this meant that... for that one fraction of a second that the bullet passed through him, it had taken the space of his heart. His heart, the organ that kept you alive, showed you were alive by beating even if other pieces of your body were to fail, it had ceased to exist. No matter how briefly it had been, there had been a second where he hadn't had a heartbeat, where he had been... dead.

It … kind of made sense? He... died... his heart got destroyed... The box had picked up on it and had crashed, put out his light of life at that exact moment and... normally one couldn't come back to life. Once you were dead, you were dead, there's no coming back... He was probably one of the only ones in life that could accomplish the feat of … dying … and coming back practically the same second. Have his heart destroyed only to have it beaten again as if nothing happened moments later.

He was shocked himself at the realisation that, yes, he died. He died. He had been dead. He... he should stop using his power like this... to poke fun at the enemies like this... He didn't know himself he could 'return from the dead', never thought of it like this... There was a chance that... his devil fruit could have disappeared in that fraction of a second too, they leave your body the moment your dead. Which he had been, the black box in Ace's hand proves that. If his fruit had left him... he wouldn't have been able to heal, he would have perished on the spot and... Ace would have really come home to him dead.

The arms he had around his freckled lover tightened and he squeezed his eye shut. "I'm sorry Ace. I'm sorry. I'm so sorry." He apologised for minutes on end before he stared changing his words, and rocking the other again "I love you, I love so much Ace. I'm here. I'm alive. My heart is beating. I won't leave you."

Ace never let go of him, not even when he passed out again after a while, and he didn't care. He didn't want the other to let go, he didn't want to let the other go. Standing up he put the other into the bed, joining him and laying next to him, covering them both with the blankets as he held the other close. A few tears final left his own eyes as he kissed dark locks, whispering more words of apologies and love.

They would get over this together, he would made sure Ace healed from this experience. He would proof that he was alive. That, even if the box that represented him didn't show it, he was alive, and that he wasn't planning on leaving Ace any time soon. And maybe... Maybe someday his box will get colour again and the light would shine brightly again. He prayed that it would, he knew the comfort it brought to his lover. But even if it didn't, he would be there to physically show Ace every day, every moment, every time he breathed, that he was still there.

He gave one more kiss to soft dark locks before giving in to the exhaustion that had been pulling at his limbs since a while ago. They would get over this.

I got the prompt from this story from a Soulmate AU list '(E/In)ternal Noise' made on Tumblr. I litteraly made a request to someone awesome to write the prompt out for me, but I couldn't stop myself from writing a version too.
The original prompt that I edited a bit was: "Everyone has a device to check if the other person is their soulmate (like a light that's red when it's not and green when it is). It gets brighter when they're full of life, dimmer when they get sick, and out of batteries when they're dead."
I just changed it to the device being personalized in a favourite colour of your soulmate, the light also being this colour. And it just is always this one colour, it doesn't change.