Introduction. This happens some time around chapters 11-13 of Revolution. Just more stuff about the Original 13. They seem to be dominating the spare parts chapters of late.

"Are you certain you sensed dark energon here?" Prima's solemn voice echoed in the hallway.

"It was out in the arena. Come feel it for yourself. I don't like that it's here. We're right above…" Solus didn't want to say it out loud in case Megatronus was listening somehow. Vector Sigma was here at these coordinates—right beneath the gladiatorial arena. It was a miracle that the mecha who ran this place hadn't noticed it. The chamber wouldn't open unless someone with the key was present, but if someone had realized there was space unaccounted for, they could have broken into it.

And if Megatronus was here and had found it… that could mean serious trouble.

She stepped out into the center of the arena, all senses on their highest settings, listening, smelling, feeling for the elusive presence of Unicron's blood.

If this trail ran cold, they'd scour Kaon for him. They had absolutely no other leads so they might as well...

There.

There it was, faint but distinct. Not quite a feeling, not quite a smell. She stepped toward it, focusing on the discordant hum in the back of her spark.

"Solus?"

"This way," she said, and he followed her to the edge of the arena.

"I feel it as well," Prima declared, looking up at the wall that had stood between fighters and spectators.

Was it coming from the stands? Solus wouldn't be surprised if Megatronus had frequented the gladiator matches.

"Come," Prima said, and led the way toward the door. Solus followed, careful and a little bit nervous. If Megatronus had been physically present, she would have felt the dark energon more strongly, but it was still unsettling to know he might have been here.

Prima led the way through wrecked halls and broken doors to the stands, where they followed the feeling of dark energon to the best seats in the arena—private boxes with larger chairs and a clear view of everything. These were seats for the mecha who owned this place.

Prima knelt on the floor and rested his hand by one dried dark splotch on the ground. "This is old."

Solus forced herself to relax and commed Maccadam.

He answered promptly. "Hey, Sol. Find something?"

"We've found traces of dark energon in the stands, just like I felt. And they're not just anywhere, they're in a private box. Someone with a lot of credit or who was involved in the gladiator fighting business sat here. It's old, though. Could have been here for half a vorn."

"Hmm," Maccadam said. "A cold trail, you think? And I mean, our Megatronus isn't the only one who's ever used dark energon. I can look into the owners of the gladiator arena, see what I can find, but..."

"Are you speaking with Alchemist?" Prima asked.

Solus nodded.

"Ask him to look into the organization that ran this place," Prima said. "Meanwhile, we'll search the rest of the building."

"It might not be Megatronus," Solus said. "It doesn't seem like him, running a place like this. Wouldn't he be worried that someone would notice him, even though he probably doesn't look like he did last time?"

"He has been unpredictable in the past." Prima said. "We can't afford to ignore this."

"The mech in charge couldn't have been him," Maccadam said over the comm. "That mech's designation was Clench, and he was definitely not Megatronus. He apparently had blue optics, and is confirmed offline. Of course, I really can't see Megatronus being some sort of henchman either. He didn't even stick to serving Unicron for very long."

"Right," Solus said. "Well, we'll look around and see what we can find."

"So will I. Good luck. Stick together."

"We will." Solus cut the comm. and turned to look at Prima.

"Well?" he said.

"Maccadam says we should keep looking, and he'll see what he can find out."

Prima nodded once. "Let us remain together. We cannot risk Megatronus surprising us. Remember, it may have been he who killed Onyx."

"If it was, we'll make him pay dearly." Solus pulled her axe out and followed her brother the way they had come.

With the mortals starting another war, it was going to get easier and easier for Megatronus to come back to Cybertron undetected. And if he was already here, it would be easier for him to hide.

They had to locate him quickly.

There was a certain anxiety that came with being hunted.

But he was used to that.

Used to being on his own, looking over his shoulder all the time, staying in the shadows. He was used to keeping his optics open, watching the places he'd been and the places he was going to be.

So while he wasn't sure how long ago Prima and Solus had picked up his trail, he was still far ahead of them.

That was good. It gave him space to turn the tables. Life was much more fun when he was doing the hunting. If he was honest with himself, he was glad that they'd found him, because it gave him an excuse to stop lying low.

Rumor had it Primus wasn't bringing them back anymore.

That meant if he offlined them they would stay offline.

He couldn't waste such a wonderful opportunity.

He watched them out of the skyscraper window—they were just two specks in a crowd of hundreds, but they stood out like fresh energon on a white painted wall. Stupid idiots had never learned to fit in. They just barged through everything recklessly, as if they were infallible, unstoppable.

But they weren't so good at everything as they thought they were.

If he fought them, he'd want to do it somewhere he was familiar with. And he'd want to fight them individually. On a good orn, he could beat either or even both of them separately, but he didn't want to risk them fighting him together.

How to separate them, though?

Prima was even-tempered and stubborn. If he'd decided to stick with Solus, then there was nothing to do about it.

But Solus… Solus could be lured away.

The beginnings of a plan formed in Megatronus's helm, and he smiled at the small, oblivious specks below that were his brother and sister.

Then he turned and faced the room. It was a bit of a mess. Overturned chair, dented wall, energon all over the floor. The mech and femme who'd lived here hadn't been too keen on a stranger coming in and borrowing their window, but they weren't complaining about it anymore.

He walked past their offline frames, and let himself out, then shut and locked the door behind himself.

As he made his way out of the building, he wondered whether anyone was watching him—whether there were cameras in the walls.

He should be a little more careful. Killing mecha wasn't dangerous right now, because the city's new leader had effectively wiped out enforcement, but he didn't want to get sloppy.

That mechling gladiator was an idiot. He'd just gotten lucky. He hadn't even started his rebellion on purpose, he'd just opened his stupid mouth a little too often during fights. And now he was ruling Kaon like the amateur he was…

It was hilarious.

Megatronus was so proud of him. A tiny bit offended that he'd shortened his designation, but still proud of the little protégé.

Some orn, that mechling might accidentally do what Megatronus had been attempting for centivorns, and bring down the entirety of Cybertronian civilization.

Megatronus left the building. He took side streets and short-cuts until he was certain he was ahead of Prima and Solus. Then he pulled out a cube of dark energon. He dipped his finger in it and smeared it so lightly on a wall that when it dried you wouldn't be able to see it.

But Primus's pets were good at sniffing the stuff out.

He crept around the slums, leaving traces of dark energon here and there. He wanted them to know they were on the right track, of course.

Then he retreated to one of his favorite maze-like neighborhoods. He frequented the place often enough that the mecha here knew him. They didn't know exactly who he was, but they knew not to bother him. Some of them even knew the designation he'd been going by recently. He was proud of that designation—it would be annoying if his siblings found it out and he had to come up with a new one. In old Cybertronian, it had a similar meaning to the title history had given him. But instead of suggesting he had fallen, it meant he was a fall—a catalyst of falling—an overthrower.

He found a dead end and poured dark energon all over the ground so the sweet, powerful smell of it would stretch out to fill this part of the neighborhood. Then he went around and left pools of dark energon in several other places as well.

Normally, he couldn't get too close to Solus and Prima without them noticing him.

But, of course, if there were even stronger sources of dark energon nearby, his presence would be masked.

He ran through his plan again in his helm.

Find Prima and Solus again. Follow them from a distance until they found this neighborhood. Sneak up on them, make Solus angry, separate her from Prima…

If it didn't work, then he'd leave the city and let them wander around looking fruitlessly for a while. But if it did work, then he'd kill one or the other of them.

They should really expect this by now. They should really be more careful.

But he was glad they weren't.

He was always pleased when mecha underestimated him, when he had to earn their respect the hard way. That was how you knew it was you, not your size or your toys, that they were afraid of.

He paused in an empty alleyway and pulled a long, sharp blade out of subspace. He preferred to kill with his bare hands. Any fool could stab someone, but you knew you'd mastered the art of death when you were your own weapon.

He'd make an exception for his siblings, though. He'd do anything to get rid of them.

"And that was all?" Maccadam said. "No mech with purple optics?"

The gruff-looking mech shrugged, then took a long draught from the large cube of high grade Maccadam had given him.

He was a two or three words per sentence type of mech, which was more than a little frustrating.

Solus and Prima had found more dark energon in a little out of the way room in the building where the gladiators had lived. But there was no way Megatronus had been a gladiator. He'd never have let anyone catch him fighting on camera, in case Maccadam saw him and recognized him. Furthermore, if he'd been a gladiator, he'd be unstoppable, and Maccadam would have heard about him. It generally took two or three of the original thirteen working together to beat him in a fight. The only one who could take him down single-handed was Vector, and that was only because Vector could teleport.

"Yeah," the big mech said. "There was one."

"What?" Maccadam said. The mech had taken so long to answer he'd forgotten his question.

"There was a mech with purple optics."

"There was? But you said there wasn't anyone high up in Clench's organization with…"

"No," the big mech said. "Don't know who he was—he was just there sometimes."

"What did he look like?"

The mech drank the rest of the energon. "Small… don't know. Didn't pay much attention."

Maccadam frowned. "And you don't know what he was doing there? You don't know if he was a guard, or a gladiator or…"

"Never saw him fight," the mech said, staring sadly into his empty cube. "Don't know, Mac. I just went to a lot of matches is all, cuz I had a friend who'd get me tickets."

"Do you know where that friend is? He might be able to tell me—"

"He's dead, mech,"

Oh. Right.

"Okay," Maccadam said. "Is there anything else you can tell me about the mech with purple optics? Who did he sit by? Where did you see him? Did you see him anywhere besides the stands?"

"He kinda had his own box," the mech said. "Maybe he was a sponsor? That's all I know, really. He's probably dead too, considering what happened in Kaon."

Maccadam nodded. "Thank you. Let me get you a refill."

"Thanks, Mac. Hey, was that helpful?"

"Yeah," Maccadam said. "Helpful enough."

"Who is this mech you're looking for?"

"The Fallen."

The big mech snorted. "I mean really. Who is he?"

Maccadam smiled sadly. "He's a friend. Or he was, a very long time ago. But now there are things he needs to answer for."

The gruff mech nodded and Maccadam went to get him some more high grade. He got a message from Amalgamous and opened to read it as he slipped behind the counter.

It was nice to be in touch with his siblings again. That was one good thing about the impending end of the world—they were all talking to each other now.

Of course, Amalgamous was several hundred light vorns away at the moment, so a comm. still wasn't possible, even with their advanced communication systems.

Maccadam read the message.

[Hey, Alchemist. Quintus and I are snooping around the site where we found Onyx's frame. I don't know why we're bothering, but Quintus seems to think it'll lead somewhere. My personal theory is that Vector lost it and killed Onyx, but no one will listen to that. In any case, Quintus found some rocks that he says might actually have something organic in them. I have no idea why that's relevant, but he seems to think it is. He says he can't analyze the organic stuff without a proper lab, though, so we're going to try to send samples back to you. We'll give them to Micronus if he starts answering his comm. but otherwise we're going to need the space bridge, so if Solus and Prima aren't busy, you should send them out to activate it. And if they are busy, you should come yourself. Then maybe you can trade places with me. I'll watch your little bar, and you can wander around in space with Quintus and say sciencey things to impress each other. Either way, thought I'd let you know. It's sparking boring out here, so I hope you're enjoying the fireworks at the end of the world.]

Maccadam sighed and brought his informant another cube of high grade, then went back to stand behind the bar.

Solus commed him.

He smiled. He was very popular this orn.

He answered Solus. "Hey, any luck?"

"Alchemist! Megatronus is here, frag it!"

"Wait, what?" Maccadam said.

"I was chasing him down but I lost him. I need a bridge, though because… oh, Primus, no…"

"Send me your coordinates," Maccadam said, knocking a couple of cubes over in his haste to get to the door behind the counter.

"Prima and I got separated…"

"Pit," Maccadam said. "How?"

"Megatronus came out of nowhere, stabbed Prima, and ran off. I chased him, but he disappeared. Frag it, I left Prima behind and he's hurt. If Megatronus circled back…"

"Give me Prima's coordinates then," Maccadam said rushing down the stairs to the third basement where the groundbridge was. "I'll open a bridge."

"I don't want you to fight Megatronus alone. I'm almost there."

"Just give me the coordinates!"

She sent him the coordinates and Maccadam made it to the bridge and started powering everything up and putting them in.

"No!" The rage and horror in Solus's voice sent a chill down his back plating. He opened the groundbridge and stepped through, cutting the comm. with Solus as he did so.

On the other side of the bridge, he found himself in a dim, rusted-out street filled with the overpowering stench of dark energon. His vents seized up and his spark shuddered, but he tried to ignore the sickening feeling, looking around instead. A small figure he assumed was Megatronus was sprinting away down the narrow street, with his sister giving chase.

"Solus!" Maccadam shouted, rushing after her, then stopping when his pedes skidded on energon and he nearly tripped over Prima. He looked down and froze.

He heard Solus's pedes hitting the ground as she jogged back in his direction, but he couldn't tear his gaze away from his brother.

Prima lay in his own leaking fluids, chest plate shattered. Spark energy emanated wildly from the blade of a knife still sticking out of his exposed spark chamber.

"No…" Solus breathed. "Primus, no…"

"Let's get him through the bridge," Maccadam said, slipping numb hands under his dying brother's frame. "I've got some life support equipment at home."

Solus turned to look down the street as Maccadam picked Prima up. That wound would have killed an ordinary mech instantly.

Prima didn't have long.

"Come on, Solus, we don't have time."

She growled, but followed Maccadam through the bridge and closed it behind them.

Prima jerked, nearly pulling out of Maccadam's arms.

"Hey, hey!" Maccadam said. "Hold still. Sol, help me."

Solus grabbed Prima as well.

"No!" Prima choked, thrashing again. "Koh… in…"

"It's okay, mech. Don't try to talk, let's just get you on a medberth."

Prima gasped, coughed once more, and then went limp. Solus and Maccadam rushed across the hall to Maccadam's private medbay, where they set Prima gently on the berth.

Maccadam dragged over some life support equipment and went to pull the knife out of Prima's spark chamber, but then stopped. The blade of the knife was no longer lit from beneath.

Prima's spark was gone.

He was gone.

Maccadam felt cold.

"Mac?" Solus breathed.

Maccadam shuttered his optics, bowing his helm

"He's not…"

He was gone.

"No… this is my fault I should have stayed with him! No, no, no!"

"Solus…" Maccadam looked up at her.

She took a step away, trembling, venting hard.

Maccadam followed her and wrapped his arms around her. "It's not your fault."

She tried to pull away at first, but then gave in and simply screamed anger and horror and guilt into his shoulder.

Maccadam held his sister even more tightly as the reality of what had just happened sank in. He couldn't believe this. He didn't want to believe it—didn't want to think about it. Maccadam hadn't always agreed with Prima about everything, but he was their uncontested leader. He'd always seemed to know what to do.

And now he was gone.

Notes:

1. No it's not an April Fools joke. Prima is actually dead. :( And the Fallen is at large, causing problems and trying to kill the rest of them. Yay.

2. Also, if anyone was wondering, whenever I say "old Cybertronian" that translates to Latin for Earth. So, like, if someone ever says anything in Latin (no one probably will, because I don't personally know Latin and I don't trust google translate to give me more than single word dictionary definitions) that means they're speaking in old Cybertronian. Or if someone has a name that means something in Latin. (Optimus, for example, or like, half of the original 13) that means they have an old Cybertronian name. I don't think that's canon, it's just something I came up with to explain all the random Latin.

3. Thanks for reading!