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Part 2 of ABO Tsams AU - Omega Sun
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Published:
2025-06-26
Updated:
2026-03-02
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39,233
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6/?
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Goodbye Nexus - With Wayyyy more Sexual Tension

Summary:

After his passionate exchange with KS, Sun goes back to the Moon and together they begin their plan to send Withered Nexus to the solitary dimension. Sun wants to be the one to say goodbye to mixed results.

Notes:

I was super surprised at all the comments on my last work and it really motivated me to start working on the next part! I absolutely want to turn this into a full fledged story with arks etc. Please be patient as I work on this. It's been an absolutely delight to make an ABO au based on TSAMS.

This will have non-con elements but won't cross the line. If that still makes you uncomfortable please don't read.

Minors do no interact.

(See the end of the work for more notes.)

Chapter 1: Chapter 1: Sun's family isn't happy

Chapter Text

After everything Sun portaled back and stumbled through the entryway of their shared home.  He winces as he can’t stop the soreness in his hips.  Immediately Moon runs at him and envelops him in a hasty hug.

 

“Sun!”  the Twin shouts as he pressed himself to Sun and scents him lightly.  Moon rubs his wrist around on Sun’s face plate and does his best to cover up KS’ scent.  He pulls back with a growl and the naptime attendant’s claws come out.  Moon looks frustrated as his canines protrude.  “Y-You!  You actually-He actually-”  The smarter twin was at a loss of words.  “Fuck…Sun…Fuck!”  

 

Moon pulls the rim of his hat down as he growls some more.  “I didn’t want this-!  To you of all people…Great Freddy Fazballs…Sun you just-you smell like him-!  Just…Shit.”  A frustrated hiss was pulled from Moon’s vocal box.  Moon’s own alpha scent fills the space with a heavy stressed feel.  Sun’s nose wrinkles as the anxious smell assaults his sensors.  Wilted mint and moldy blueberries.  Sun resists covering his nose.  

 

Moon was shaking and Sun just felt so, so tired.  His battery was run through and his emotions were completely exhausted.  “I know.  I know, Moon…just…can we talk about this later?”  Sun can’t stop as he reaches up to smooth over Moon’s night cap.  It’s a rare instance where Moon would allow him to touch it.  “We have to do this now.  Sunsh-KS…KS said he’d go over there in just a few minutes.  We don’t have much time.”

 

Moon can’t stop shaking with growls, “I hope that Void-Nexus emo, bastard kills him before we show up. If he somehow survives, I’m going to dismantle KS screw by screw-!”  Moon’s scent was filling the room with agitation, the moldy berry and old mint smell was replaced by something more astringent.  Sun’s nostrils burned and he bit back his own whimper as past memories were dragged up.   He keeps himself steady for Moon.  Sun knows he needs to keep it together so his twin can stay on track. 

 

“Moon, please.”  Sun pleads, hoping Moon will focus on the task at hand.  “We need to meet the others.  Monty made the teleport device right?”  Sun reaches out and gently grabs at Moon’s blue wrists.  He brings Moon’s hand down and cups them carefully.  Sun adjusts the dark sleeves of Moon’s turtle neck and Moon’s fans kick in.

 

“...”  Moon makes another chuffing huff.  “Monty has everything ready.  They’re with Solar right now and both are at the lab.  D-Do you need to sit down or s-shower?  You don’t need to come if you’re tired.”  Moon willed his claws back as he carefully stepped away.  Not able to look Sun in the optics.  “You also…smell…like KS…and other stuff.  I don’t think the others will react well.”

 

Sun shook his head, “We don’t have time.  I can clean off later.  I can even charge at the lab if my battery gets too low.  Please…I need to be there when we finish this.  I can’t just…rest when we’re sending Nexus off.”  

 

Moon nods in understanding, “I…I’m sorry brother…..I wish we could..I know you didn’t want th-”

 

“Moon, why are you sorry?  I agreed and left to do my end of the deal with KS.  It’s okay, really.  I want to be a part of this.  I’m all in.  We can talk about what me and KS did later but not now.  Seriously.  I promise”  Sun hoped after everything Moon might drop things and he can move on without talking about KS.  Sun promised but honestly doesn’t want to share the details with his twin.  His sordid love life should remain a secret.  However, Moon is worried and he wants to do everything he can to soothe that worry.

 

Sun has a sour look on his face, he did his best to cover his unsteady gait as Moon opened a portal to his lab.  Moon shoots him a wary glance and even offers a hand out to help Sun walk more steadily.  Sun minutely shakes his head and pushes Moon’s offered hand away.  He wants to walk on his own.  

 

They both stepped through the glowing white portal into the chrome fixture.  Sun feels slightly invigorated to be so close to his magic source once again.  His battery absorbs the ambient energies.  Sun’s body relaxes like he’s letting out a faux sigh of relief.  The yellow colored animatronic slightly wilts as some of the stress that was keeping his back rigid leaves him.

 

When the twins walk out of the dark hall into the main lobby of the lab the air seems stagnate.  Sun’s fans stutter slightly as a different growl fills the air.  Monty and Solar stop mid discussion to stare at the two.  The smell of two wary alphas fills Sun olfactory sensors and he stumbles back slightly startled.  Solar was literally raising his hackles, Sun made a surprised and wary chirp.

 

Solar’s burnt sienna eyes zero in on Sun.  He bares his alpha fangs and can’t stop the warning growl that leaks from his voice box.  Sun’s eyes widen in quiet horror as Solar alpha fangs are pointed at him.  Moon twitches before he steps to block Solar’s view of Sun.  Sun accidentally lets out his own distressed smell and he watches as Solar whips a gloved hand up to cover his snarl.  Solar’s own alpha pheromones fill the air and Sun can’t help but feel slightly…unsafe…

 

The air was hostile and he stepped slightly more behind Moon to hide himself.  He hates that he needs to reach out and touch Moon's shoulder to feel somewhat secure.  Moon himself bristles as the orange and red animatronic seems to flip flop between hostility and confused agitation.

 

“Why does he smell like that?”  Solar asks, his usually tired sounding voice laced with a new unknown edge.  He huffs between his words and the Lab seems to fill with an angry blood-lust like sting.  The shadows seem to grow darker in the Lab and Sun tries his best to not let this  moment affect him.  Solar kept a hand covering his snarling mouth and the other grabbed at the console he was standing at.  He hisses as the leather gloves creak 

 

“Solar, Solar!”  Moon’s voice cracks, “Easy buddy, It’s just Sun!  He just…smells…different at the moment, that’s all.  Calm down, buddy.  It’s not a big deal.”  Moon can’t tactfully word Sun’s situation.  “Look…we have assistance with Nexus.  Killer Sun is helping us right now and we don’t have much time.”  Moon walks up with Sun trailing behind.  The closer Moon gets to his fellow alphas the more Sun trails back.  Lagging behind a bit Sun tries his best to hide his limp, Sun leaned against the rails of the stairs.  His rays shrink in and he grimaces in pain, he never knew being railed would make him this sore.

 

“Wow, Never saw this coming from you, Sun.”  Monty teased, “You can sit this out.  We’ve got this.”  Monty waves off as they turn back to Solar and Moon.

 

Sun hates the look of realization and disgust that runs through Solar’s emotes.  Solar probably already figured out why Sun smells like another alpha, figured out why they’re getting help, even when his eyes dip down to Sun’s feet to watch his steps, the judgement feels all consuming.  Monty’s own statements don’t necessarily help to hide what he did.

 

Sun doesn’t even bother to look over at Monty.  He just curls in on himself in shame, Sun debates if he really wants to sit down but giving Monty the satisfaction makes his stomach twist with ugly feelings.

 

Solar comes closer to Sun, his eyes having an unknown glare in them.  His eyes keep roaming up and down Sun’s form which makes the omega uncomfortable.  “I don’t know what happened…but I really can’t stand how you smell right now.”  A feeling of hot shame courses through Sun as he looks away and does his best to not cry.  Something soft is shoved against Sun’s chest and his opalescent optics look up at Solar in confusion.  He makes a perplexed mechanical beep at the other.  

 

“Wear this o-or rub it on you o-or something.  I can tell Moon scented you now that I’ve calmed down.  Sorry for the overreaction Sun…”  He trails off and awkwardly gestures to the well used fabric.  Sun realizes it’s something the alpha uses a lot due to the old stains and wear on the soft cleaning cloth.  Before Solar can choke on more words he reaches over and rubs his inner wrist near Sun’s neck peg.  

 

A shiver runs through Sun and he almost coos, Solar sometimes feels like an awkward kit of his own.  He knows Solar has always been awkward around him and the awkward way he gave him something of his own made Sun’s mechanic heart swell.  Smelling like another alpha really set his pack off didn’t it?

 

“It’s ok…I was just startled.  I’ll use this, thanks.”  Sun awkwardly thanked Solar as he wrapped the cloth to his neck.  It’s like a messy handkerchief.  Sun feels a bit better about all this.  His scent was blended with KS’, Moon’s, and Solar’s now.  
Sun was always jealous of Solar’s scent, to him it always was like orange zest mixed with cinnamon and allspice.  A warm Mala chai drink of sorts.  Moon’s was always a soothing balm.  His twin carried the smells of blueberry, mints, and lavender.  Monty’s scent…isn’t the best to Sun.  He knows Earth describes it like a natural field full of cat grass and pollinating bees.  Sun never got the comparison.  Everyone smells pheromones slightly differently and for some reason Sun always smelled pheromones like foods.  

 

Solar just nods, “Don’t do this again.”  He almost orders, “...Please.”  Solar coughs into his hand as he circles back to the other two alphas.  Moon gives a cheeky smirk and punches Solar on the shoulder lightly.  Monty himself pats Solar on the back and they go right back into their argument.  Sun stands there numbly.  

 

His stomach does angry, anxious flips as he listens to them bickering.  The alphas are all arguing about who should go and use the device to permanently strand Nexus.  That horrible churning sensation fills Sun and his insides feel like they’re full of bricks.  He looks at the remote.

 

Every now and again the three keep glancing back to check on Sun.  Solar in particular seems to have a hard time hiding his own grimace.  Moon always waves Solar’s attention back to their argument.  Absolutely no ground was being gained as they all argued away.

 

Moon once again was spouting about his own self sacrificial bullshit and Monty was also trying to be brave too.  Solar even added his own wrench into the ring of who’d go and face the Wither-Nexus.

 

Sun hopes KS is okay.  He hopes Nexus is okay.  It’s a horrible split of his own desires.  KS said a lot of things when they were together.  Made a lot of promises.  Sun realizes that was probably all pandering just to get him soft and compliant.  

 

Sun wanted to shrink away in shame, no Alpha ever wants him.  It’s much better to believe that than to buy into some kind of secret romance.  Sunshine…if that actually is his name, wouldn’t use sex as a bargaining tool if he truly meant the things he said.  He just played Sun’s heart and body and he let him, the exchange of services was too promising.  Moon wasn’t hurt for once, Sun actually made himself useful, KS was satisfied, no life spans were exchanged, and Sun had fun…it was fun.  

 

It was fun.  

 

Sun doesn’t dwell on the confession Sunshine gave him at the end.  He’s a burnt out omega and getting his hopes up over this will be too devastating.  

 

Sun goes back to paying attention to the argument.  It was seriously still going on?  His white optics roam over to the very simple device on the console.  It looked almost like a cartoon remote switch.  A silver box with a bright red button on top and an antenna.  

 

“H-How does it work?”  Sun asks meekly from his resting spot on the stairs.  His hips were slowly turning into a dull numb, something he can manage-ably ignore.  The yellow animtronic’s paint glitters dimly in the lab light as his hands awkwardly tugged at one another.

 

“It’s pretty simple, just press the button once to get to the solitude dimension and then press the buttons twice to come back.  I made it as idiot proof as possible, Sun.”  Monty answers smoothly.  The gator barely turned to address Sun, still working to actively keep Solar and Moon from risking their hides.

 

Moon nods with pride, “Yeah, we spent ages on finding the place but actually making the device was easy work.”  

 

“It wasn’t that easy, Moon.”  Monty cuts in, the gator has to iterate their labor,  “Building this baby in the time I had is nothing short of a miracle.”

 

Sun stares at the device, it’s that easy?  That easy?  Just a couple of presses…and he’d be done.  Sun looks back to the alpha crowd.  Solar’s been so absorbed into the discussion he forgot to look back at and judge Sun.  Moon also completely wrote Sun off once again and Monty was doing their usual thing of not even bothering to look at Sun.  

 

It was a big deal when he walked in, smelling of another alpha, but the moment his scent was covered up he was written off once again.

 

Solar was pacing in the lab anxiously and eventually stood between the two.  Sun could make out Solar volunteering himself to go in their stead once again.  The mechanic was gesturing frantically.  The three were just arguing in circles on who will go and time is quickly dwindling.  KS is still fighting Nexus right now and Sun doesn’t want to keep wasting time.  He sacrificed his metaphorical cherry so they could have this chance and they’re all still waffling around.

 

No one even noticed when Sun swiped the remote and ran out of the room on shaky legs.  Sun darted into the next room and he felt his magic sing as he once again cast a teleport spell for the night.  He ignored any frantic calls sent his way.  Sun muted the phone in his head as he felt a new determination filling his yellow frame. 

 

-✸-

 

Sun felt himself materialize at the daycare, his legs gave out and he collapsed to his knees as his fans vented out his stress.  He was shaking from the adrenaline coursing in his robotic body.  He clutched the teleport remote to his chest and peaked into the daycare.  The clang of knives and small explosions filled his audio receptors.  He sucked in an awed breath.  

 

From the gap of the daycare doors Sun watches as KS does a series of cartwheels to dodge a volley of dark matter bombs. 



“You’ll have to try soooo ~ much harder than that to hit me big boy!” KS did another back flip as Nexus let out a heated growl.



“I thought you said you’d fight me!”  Nexus screams as he charges him.  NSP makes it so Nexus practically teleports into KS’ space.  He pulls a hand back and his scythes protrude dangerously.  He swipes at the other who dodges it narrowly.  KS uses this close proximity to lunge at Nexus and claw him across his chest.  The nicks leak purple ooze and Nexus barely flinches as he tries to grab KS by the scruff.

 

KS ducks down and dives in between Nexus legs.  He rears a knee up and wacks Nexus right in the family jewels.  Nexus just growls at him and aims a powerful stomp at the Killer Sun.  Killer Sun moves his leg out of the way just enough.  Nexus’ stomp perforates the soft daycare plush floor.  

 

“Stop moving!”  

 

“But that’d ruin all the fun!”  KS counters as he reaches into his pants.  He pulls out two oversized machetes.  The rugged metal shines in the night mode of the daycare.  KS gives them a flourishing twirl as he throws one right at Nexus.  Nexus uses his shadows to fully faze through and dodge them.  KS smirks as he quirks his extended finger.  The machete bounds back to Nexus, the thin wire attached to KS hand glints dangerously as he tosses the second knife into the mix.

Nexus carefully dodges around the twirling machete blades, “I’m going to kill you!  You ANNOYING LITTLE PEST”  He screams as he tries to cut the wires in two.  He sends out NSP blast after NSP blast.  The purple arks sail through and destroy various play structures.  Large booms shake the side of the PizzaPlex all this action was going down.  The play place catches fire and slowly melts into itself.

 

Nexus and KS ignore the carnage around them as they engage in hand to hand combat.  Nexus tries to use his overwhelming power and size to try and incapacitate the dangerous Sun model but the experienced killer uses expert movements to shut down every deadly advance.

 

Purple flames surround them as KS carefully wraps his wires around Nexus.  The other was too angry and agitated to remember to phase through.  He summons a powerful wave of wither storm energy to push KS and his wires back all at once.  The external force takes all the kinetic energy from the blades and they’re grounded.

 

Sun’s fans stutter to a stop as he keeps up his peeping act of the high octane fight.  Sunshine moved so fast and was insanely dexterous he was not only keeping up with, but pushing back, Nexus.  Even when he used his NSP and Wither abilities.

Sunshine tuts at Nexus.  “You took all the fun out of my attack!”  He leans back casually as Nexus presses him back into close quarter combat.  With a flick of the finger Sunshine’s wires gleam and the two knives he was tossing around both flew up and slotted into place in his hands.  The killer Sun successfully stopped Nexus’ scythe arms with his two weapons.  The clang and spark as they collide.



Sun’s optics have trouble keeping up with the fight as the two start to move so fast their arms are just a giant blur.  Eventually KS dives between Nexus’ legs and does a roll to gather his wires.  He wraps Nexus and uses the play structure that wasn’t currently on fire to vault over the play bridge.  With the wires in hand he catches them against the bridge and yanks. 


Hard

 

Nexus is coiled tightly and with a frustrated scream he’s hauled into the air and launches through clear to the cardboard cut out of the daycare’s castle tower,

 

“Bet you didn’t see that coming?  Moons never see that coming.  They never think to use the bridge.”  Sunshine taunts as Nexus gets out of the ball pit he landed in.  His rage simmers and the plastic balls all start popping one by one.  He even stomps on one as he pants out clouds of noxious NSP fumes.  

 

“DON’T CALL ME MOON!”  Is what Nexus took from the taunt.  He launched back KS with a powered kick off.  He throws his arms out and does a deadly twist, basically a NSP saw blade hurting at KS with mach velocity. 



“Shi-”  Sunshine can’t finish his curse word as he’s bowled over by the angry wither storm vessel.  The two bound around and sail right into the daycare walls. 



Sun himself has to scramble out of the way hastily as they both shoot through the daycare walls like they’re made of cardboard.  Standing in the lobby of the daycare Nexus stands on the black and white checkered tiles. 



His form hunches as he pants with rage.  “...”  He stares at the alpha for a moment.  “...Why do you smell like that?”  He asks a pile of rubble.

 

With a sturdy kick KS jumps out and cuts the rubble around him with his razor sharp wires.  He picks himself up with a glare.  His own maniacal grin never faltered even after he was fully bodied by the other. 



“You smell like him, you smell like him, why do you smell like him, did you touch him?  Why do you smell like that? Why? Why? Why? ”  He mumbles as he grabs at his head with a grunt.  Nexus growls as he walks over to the two parked toy racing cars. 



Ever since they broke down, Solar left the two daycare themed race cars next to the un-used Glamrock charging station because he intended to fix them.  However, the mechanic slowly got more and more busy to the point where repairing those carts was soon forgotten and they instead just became a part of the daycare lobby decorum.  Nexus picks the Moon themed car up like it was made out of feathers.  His grip crunches the car and he shakes with more suppressed NSP and rage. 



“Oh. Oh!   Hehehe, you smell Sun don’t you?  Does it make you angry?  You disowned your brother but you’re angry when another claims him?”   

 

Nexus let out a howling scream as he threw the moon themed car at KS.  KS threw his wires and they wrapped around the fake palm trees in the lobby.  He tugs the wires to help assist him in a hasty dodge.   

 

“No-No-NO!”  Nexus starts screaming as he bombards the other with air blades of NSP.  Every tantrum-like swipe of his arms sends a dangerous careening of deadly purple energy.  “You didn’t!  He’s MINE.  SUN IS MINE”

Sunshine darts around the air blades, he even masterfully jumps and curves his body to coil around them like a spring.  His rays also dodge the energy by centimeters.  Sunshine cuts it in close to Nexus and stabs multiple smaller knives into Nexus’ void like torso.  Multiple little needle-like pricks litter the taller vessel and he stumbles back as liquid purple energy oozes from his mouth like a faux animatronic blood.  

 

Sunshine stands to his full height and grabs Nexus by the collar of his hood.  He leans in close and to an outside onlooker it looks like they’re about to kiss.  So close as Nexus chokes on his own blood Sunshine smiles, “He fucked me just so you know.  He begged me for more, over and over and I bred him.” 



Sunshine’s eyes turn into sadistic crescent as he drives another knife into the soft part of Nexus’ jaw.  The blade pokes through the taller’s cheek and slowly starts to melt from the deadly energies compromised of the fallen animatronic. 



“I made him scream my name.” 



Nexus’s eyes glow a noxious purple as he glares at Sunshine with a new hatred.  He would scream but the blade shoved hilt deep into the bottom of his jaw and neck welded his mouth shut. 

 

He’s mine now.” 



With that KS cartwheels back to avoid the nuclear breakdown from Nexus.  Even with his mouth welded shut he slams his fist down with the force of a meteorite.  His rage devastated the daycare lobby.  He walks through a sea of purple flames as he stalks back into the daycare. 



A calm fury that makes KS giggles as he climbs up the daycare netting.  He flips over to the non burning play structure and pulls out a gun.  He camps down and starts firing.  Shot after shot lances into Nexus torso, core, eyes, forehead.  Every new hold just leaked more NSP before they eventually sealed up with the void energy that wrapped around the vessel.

 

Nexus reaches out and pulls out the blade in his throat and yanks it out.  In his grip he sets it on fire and drops it as the hilt vaporizes into nothing. 



“I’m going to kill you.”  A deep, primordial, growl seeps out of Nexus.  His blood lust fills the daycare and Sun who was waiting for his chance popped back out.  He went from the destroyed double doors of the daycare and hobbled his way over to the security desk that was relatively unscathed.

 

KS was momentarily distracted at the omega in the background.  He almost shouted out in shock when he spotted the buttercup colored model.  

 

A slash cleaved through the slides and play-place.  KS had to jump off and land with a roll to disperse the force.  The play structure groaned as it fell to pieces.  A cacophony of plastic and metal clanging around assaulted everyone’s audio receptors.  Once back on the soft daycare mats KS threw his emptied gun at Nexus and it bounced off his thigh harmlessly.

 

KS was all out of weapons at this point.  His wires snapped when he had to dodge that car.  All of his knives were scattered about and his bigger weapons were melted by the toxic NSP.  His gun became useless the moment he ran out of ammo too.  Sunshine grabs at some rebar knocked loose from the play structure and gives it a mighty tug.  Once the colorful pole was free he twirled it around like an expert pole arm.

 

He stuck the sharp pointy end of his new metal stick towards Nexus as his smiles turned foul.  “I’d like to see you try. ”  Sunshine joints were all shaking.  His rays were skewed and he had burns, scuffs, and scratches littered all throughout his body.  The fight also utterly destroyed his clothes.  It was clear this was his final attack.  

 

“I will kill you.”  Nexus adds as his voice drops into a deeper register.

 

KS starts laughing, “I’m waiting big boy~”  Even as exhausted as he was, he always had energy to demean and taunt.



Before the two can continue, Sun bursts out from behind the security desk.  He flails his yellow hands out in a wheeling motion to keep himself from falling.  His hips decided to smart at him once more as he bounces around with small whinces.  KS gives Sun an uncertain look as his yellow optics turn slightly worried.  Nexus didn’t notice that moment of weakness as his burning optics now focus entirely on Sun.  

 

The entire room goes silent.  Even the fires raging on in the background seem to be muted as Sun announces his presence.

 

“Wait!  P-Please, Nexus!  Wait!!!”  Sun’s voice lets out a warping glitch as he nervously steps closer to Nexus hesitantly, “I-I just want to talk, how about we just lower the blades?”

 

After a pregnant pause, Sun tacks on, “Please?”  His voice squeaks pathetically.