Comes a Crossover

by MythrilMoth


Comes a Rider

"Henshin!"

ORANGE!

LOCK ON!

ORANGE ARMS!

Hanamichi! ON STAGE!

Everyone stared at the new arrival. Shego's jaw dropped. "Whoa. That...is some fashion statement."

"Yeah, if your statement is 'hi, I'm Florida'," Kim quipped, green eyes wide.

"Okay, that's...kinda awesome," Miles said.

"His transformation has sound effects," Chat Noir complained. "Why does he get sound effects?"

"Ours beep when we're about to run out," Ladybug pointed out.

"Yeah but that's lame!" Chat Noir whined. Ladybug rolled her eyes.

A dozen Kraang rifles pointed at the new arrival. "Transdimensional interpass detected," one said. "The unidentified lifeform which appears to be human but has equipped an unknown technology may be responsible for the transportation of Kraang to this dimension which is unknown to Kraang."

"Unlikely but possible," another Kraang said. "Query: Identify, explain method of transdimensional interpass, and confirm responsibility for transportation of Kraang to this dimension which is unknown to Kraang."

The new arrival's head turned slowly, taking in the array of rifles pointed at him. He slowly angled his swords into a fighting stance in front of him.

"Armored Rider Gaim," he said. "This is now MY STAGE!"

And with that, he waded into the Kraang droids, swords flashing. Sparks flew, Kraang electronic voices stuttering in staccato death cries as arms, heads, and torsos were severed. Rifles were cut in half, leaving smoking holes in the ground as their power cells exploded. Alien blood splattered the ground as the Kraang themselves were sliced and diced. The others fell back, staring in stunned silence.

"If Ron were here, he'd so be geeking out right now," Kim said.

"Yeah, this...is actually kinda badass," Shego agreed in an impressed tone.

Miles landed next to Trunks. "So, uhh...you're not allergic to oranges, are you?"

Trunks slapped him upside the head. "Don't start," he muttered.

In less than two minutes, it was over. The Kraang had stopped calling for reinforcements and attempted to escape, only to find their portals nonfunctional. Gaim had carved a path through their numbers; the others had come to their senses enough to take down any stragglers. Miles had captured seven of the Kraang brain creatures that survived the slaughter; they hung suspended in a bag of webbing.

Once the last droid had fallen, its occupant screaming from painful electrical burns, Gaim looked around at the carnage, lowered his weapons, and reached down to his belt.

LOCK OFF

In a bright orange flash, the fruit-themed samurai disappeared, replaced by an unassuming youth in a blue and white parka. He looked around at the collection of heroes and teenagers. "This...absolutely isn't Zawame City," he said.

"Dude, you rock," Miles said. He frowned. "A little kill-happy on the brain things, but other than that..."

A tired, sweaty Sunset walked up to the new arrival. "Come with me, I'll explain everything, umm...?"

"Kazuraba Kouta."

"Kazuraba-san," Sunset said, nodding.

Kouta smiled easily. "Kouta is fine." He scratched the back of his head sheepishly. "Anou...I should get going, I can't risk being away from Zawame City for too long."

"That could be a problem," Sunset said with a grimace. "Once you're in this dimension, you kinda...can't leave. We're working on it."

Kouta shrugged and pulled out a pink sakura lock. "I have my own way out..." The lock became a pink motorcycle, which he hopped on and gunned. A zipper opened in the air, and he drove through it.

"Huh," Shego said. "I guess he was just passing through."

Trunks frowned. "I thought it wasn't that easy to—"

The zipper opened again, and Kouta and his bike reappeared. He looked around, blinked, frowned, and drove back into the forest visible on the other side of the zipper, which closed up behind him.

"Yeah, the cute science girl was right," Chat Noir said. "Bet he shows up again."

The recovering group slumped to the ground boredly, watching and waiting. The captured Kraang borbled and squealed in Miles' web. After his fifth attempt to leave, Kouta sighed and pocketed the Lock Vehicle. "Okay, this is just getting frustrating."

"So, you want that explanation now?" Sunset asked, her arms folded.

Kouta grimaced. "Yeah."

Sunset nodded. "Let's drop by the lab and give your bike thingie to Twilight and show her how it works, she needs to study those portals it makes. Then we'll talk."

* * * * *

A bizarre assortment of ponies sat around a large crystal table in a planning room in the Crystal Palace. Princess Twilight Sparkle looked around the room, then cleared her throat. "Alright, everypony. I know you've prepared supplies for an expedition, but I want to make sure we all understand exactly where we're going and exactly what we're doing."

"Aren't we just going to the Crystal Mountains to mine some ore?" Flash Sentry asked. "That's what I heard."

"That's all we really need to know," Limestone Pie grumbled. "This is a waste of time."

"Information is important," Maud said. "Besides, I've never heard of this ore we're searching for. I want to know anything Twilight has to say about it."

"I've never heard of this stuff either," Shining Armor said. With a laugh, he added, "But then, magical studies were never my strong suit. That was always Twiley."

"All I know about it," a burly crystal pony stallion said, "is that King Sombra sent a hundred of us into the mines to hoard the stuff back when he ruled, and every single pony who went in died."

"That's not going to happen this time," Twilight promised firmly. "And I wouldn't ask anypony to do something this dangerous if it wasn't important. A lot of lives—a lot of worlds—are depending on us."

"I'm fascinated by this other-worlds stuff," Sunburst said. "I hope you'll tell me more about it on the hike to the Crystal Mountains."

"Sure," Twilight said. "In the meantime, we need to prepare." She poked the large parchment chart spread out before her. "Bulfecium in its unrefined state has unpredictable effects on pony magic. When we get near bulfecium deposits, it could nullify your magic, amplify it, or even invert it. We're all going to need to be extra careful."

"I have something that can help with that," Sunburst said. "As soon as I learned where we were going and why, I prepared special crystal amulets that should absorb any interference from the bulfecium. I can't guarantee they'll be a hundred percent effective, but they should at least protect us a bit."

"So what exactly is this crap we're lookin' for?" Limestone asked.

"Bulfecium is the most powerfully magic-adaptive mineral known to ponykind," Twilight explained. "Depending on how it's refined and what spells are used to shape it, it can create powerful magic amplification talismans, mana inversion weapons, or in this case, an alloy that can nullify and negate any magical emanations."

Shining Armor frowned. "Don't we have stuff like that back in Canterlot?"

"Not like this," Twilight said, shaking her head. "The artifact we're trying to contain is not only perpetual, it's self-amplifying. With every passing day, its destructive emanations are getting stronger. What we have back in Canterlot could maybe seal away my magic, and that's if I was sick in bed with a fever. A bulfecium alloy containment trap? Could completely seal all five alicorns, Discord, and Starlight Glimmer."

Pinkie let out a low whistle. "That's pretty scary," she said.

"Yeah, and that's why we're only mining enough to do what we need to do," Twilight said. "Once we've contained this thing and repaired the damage to the other world, I'm burying the artifact and its container in the deepest hole I can dig in Tartarus." She looked to the two crystal pony stallions at the table. "Do you have the maps of the Crystal Caverns?"

"Our maps are incomplete," the stallion from before grunted. "I'm afraid we're going to be relying on these earth ponies you brought with you to get us through this safely."

"Hey, we're rock farmers," Pinkie said cheerfully. "This is the kind of thing Maud lives for! Right, Maud?"

"I'm more excited than I've ever been in my life," Maud said without change in tone or inflection. The ponies who weren't used to her blinked in confusion.

"I still don't get why I'm on this expedition," Flash Sentry said.

"Because we need a pegasus who can get word back to the Crystal Empire if something goes wrong," Twilight said.

"And you're a guardspony, and you can carry some gear," Shining Armor said with a smirk.

Twilight rolled her eyes. "Alright. I need everypony to rest up, check your gear, get a good dinner and a good night's sleep. We leave at dawn."

* * * * *

The phantom sky of Dimension X had long since faded from view, leaving behind a darkening afternoon sky. Sunset and Kouta sat on the front steps of the school. Once she had explained the situation, Kouta scratched his head. "And I thought I had problems," he said.

Miles and Trunks emerged from the school. "Well, we locked the brain-thingies up," Miles said. "Found a whole bunch of rabbit cages in a storeroom."

"Did you get them to say anything?"

"I don't think they can talk without their robots."

"Crap."

Trunks shrugged. "I doubt they'd have anything to say we'd be interested in hearing."

"What the hell happened here?"

The group looked up as X and Brook walked through the carnage. "Where've you two been?" Sunset asked.

"We ran into some trouble on our way to meet up with you guys," X said. "By the time we were done with that, we figured you were probably already back here, so we did a little patrol on our way back." He grimaced at a still-sparking robot corpse. "Looks like we missed a hell of a party."

"So what happened with Flash? Is he alright?"

"He's fine," Brook said. "Those girls that kidnapped him are playing music with him in his basement."

Kouta stared at Brook. "What...the...hell...?"

Brook sighed. "You know, it really breaks my heart when people keep reacting to me like that." He paused. "Even though I don't have a heart."

X facepalmed. "Just...just stop. Please."

"Well, at least that's one less problem," Sunset muttered. "I'll call him later, see what he has to say."

Ladybug, Chat Noir, Shego, Kim, Trunks, and Miles converged on the front steps. "Everything's clear," Miles reported. "No more Kraang running around, nothing else happening."

"That's good." Sunset sighed, leaning back on her hands. "I don't know about you guys, but I'm exhausted."

"Yeah, I'm worn down to the bone myself," Brook said.

Everyone waited, watching him. He tilted his head. "What?"

Before anyone could comment, Sci-Twi walked outside, a frazzled, disappointed look on her face. "I've examined the portal energies your bike generates," Sci-Twi said with a frown, "and the portal devices those Kraang carried." She handed Kouta back the Lock Seed for his bike.

"And?" Kouta asked as he pocketed it.

"Well...the bad news is, we can't use any of it to send anyone home." Sci-Twi scrolled through some data on her tablet. "The only two-way dimensional gate that functions properly right now is the portal to Equestria."

Kouta frowned. "But no...I can get back and forth from Helheim just like always."

Sci-Twi gave him a pointed look. "But you can't return to your Zawame City, right?"

"Well...not yet," Kouta admitted.

"And you won't be able to," Sci-Twi said. "The Kraang portals likewise no longer function. I've tried activating them, but I had about the same results the Kraang did before you guys, well..." She coughed. "Anyway. They're dead."

"So...what's all this mean?"

"It means our world is like a roach motel," Sunset said grimly. "Anything that comes in doesn't get out."

"Ouch. Harsh analogy much?" Kim asked.

"She's right, though," Sci-Twi said with a grimace. "Any transdimensional technology or magic that works to bring someone here will fail completely once it's in this dimension."

"Wait," Trunks said, holding up a hand. "Kazuraba-san is able to return to that forest of his on his bike. We've seen it."

"Yes," Sci-Twi said, "but that isn't his world. It's..." She frowned. "Based on what he's told me about Helheim and based on the readings I took, Helheim isn't a naturally occuring dimension. It's a subspace, a pocket universe. It appears to attach itself to reality at a fixed anchor point, where these rips in space can be opened and closed to access it."

"Meaning?" Shego prompted impatiently.

"Helheim is a parasite world," Kouta said.

Sci-Twi nodded. "Essentially," she confirmed. "When Kouta showed up here, we assumed the same force that's bringing everything else here brought him. What actually happened..." Her face twisted into a sour grimace. "Our reality-bending artifact brought an entire parasitic subdimension to our universe, and he was riding around inside it at the time, so he came along for the ride."

A look of alarm crossed Sunset's face. "I don't like the sound of that," she said.

"You shouldn't," Kouta said grimly. "Trust me, having Helheim connected to your world is very dangerous."

"We need to alert Princess Twilight immediately," Sci-Twi said. "The timetable on fixing all this just got urgent. If we allow Helheim to remain anchored to our world for more than three weeks, we might not be able to get rid of it."

"And what would that mean for this world?" Kim asked.

Sci-Twi glanced at Kouta, her eyes nervous.

Kouta looked away from everyone. "The complete and total annihilation of humanity," he said quietly.

* * * * *

Two beachgoing girls shrieked and ran, covering their heads, as "Tacomusume" sprayed them with salsa. "TASTE THE FURY OF THE SEA-QUESO!" Sonata yelled, laughing maniacally.

Ikamusume watched her with half-lidded eyes. "If she wasn't one of my most loyal minions, I'd..." She sighed. "I thought we were supposed to be taking revenge on the witches that cursed you-geso?"

"In good time," Adagio said. With a grimace, she added, "We've been keeping an eye on the news lately, and Canterlot is getting a little...too wild. We'll need to be better prepared before we go back."

"And those Rainbottoms outnumber us," Aria grumbled. "Without our magic, we need to be careful before we face them again."

Ikamusume sniffed. "I'm not afraid of some stupid humans! I—" She froze suddenly, the fin-flaps on her hat twitching. Her posture stiffened, her tentacles trailing out behind her and going rigid.

"What's up?" Aria asked. "You look like you just saw a—"

"Don't you smell it-geso?" Ikamusume hissed. "It's close! It's—"

Sonata suddenly let out a shrill, piercing scream and ran past them. "RUN-QUESO!" she shrieked. "SCARY BEACH MONSTER!!"

She wasn't the only one. A half dozen people suddenly thundered past, screaming in panic and confusion.

Adagio and Aria blinked at each other, then turned back to look in the direction they'd come running from.

Adagio's jaw dropped. "What...the..."

A massive man...of sorts...stalked up the beach, long menacing strides of his sandaled feet carrying his enormous frame several feet at a time. He had blue-grey skin, long, shaggy black hair, and solid muscles. He wore green board shorts with a purple sash tied around his waist, and an open yellow-and-black shirt that showed off his formidable pecs and abs, as well as the prominent tattoo of a sun on his chest. His jaw was long, his chin prominent and pointed...

But not as pointed as his teeth. Or his nose.

His nose was long, barbed, and decidedly not human. Above that sinister nose, above a mouth full of razor-sharp teeth bared in a menacing grin, cold eyes burned with menace.

Ikamusume slowly turned on the spot, trembling.

"Friend of yours?" Aria asked as she stared numbly at the very dangerous-looking beast-man storming up the beach.

Ikamusume whimpered. "Sh-shark," she squeaked.

"SHAHAHAHAHAHAHAHAHA!!" The shark-man threw back his head and laughed. "FREE! Free to plunder, free to..." He paused, then looked around, frowning. "Free to find out what island I'm on," he rumbled to himself, stroking his chin. His eyes fell upon Adagio and Aria, and he stomped over to them. "You," he hissed. "Tell me what I want to know and I might not kill you."

Adagio raised an eyebrow. "You know, normally I don't respond well to threats. I'm usually the one making them. But in your case? I'll make an exception." She licked her lips and walked up to the shark-man, running a hand lightly over his bare chest. "Besides, how can I resist a man with muscles like this?"

"Adagio, are you seriously doing this right now?" Aria hissed. "I don't know if you noticed, but this guy isn't human!"

"Neither are we, what's your point?"

Aria facepalmed. "Not what I meant!"

The shark-man grunted. "You look and smell human enough," he said. "I'm not particularly fond of humans...unless they serve a purpose." His sharklike grin grew dangerous. "Prove useful to me."

"Hmm...I think I can come up with a few ways to prove useful to you," Adagio purred.

Aria looked up from where she was dragging her fingers down her face. "Adagio, he has some kind of freaking saw for a nose!"

"I can overlook that," Adagio said, giving the shark-man a sultry smile. "I'm more...results-oriented."

The shark-man blinked. "You're not seriously trying to whore yourself out to me," he said in a disbelieving tone.

"Mmm...I think of it more as taking an active interest in an...interesting prospect that washed up on my beach," Adagio said.

The shark-man snorted. "Shahahahaha...! You're an interesting human." He glanced at Ikamusume, frowning. "You can stop trembling, squid. I'm not going to eat a fellow fishman. Unless you defy me."

Ikamusume gulped. "I-I-I-I'll be good-geso!"

The shark-man grunted. "Two human women and a squid...not exactly the most promising crew, but until I have a better read on the situation, I suppose I have to start somewhere." He clenched a fist. "Monkey D. Luffy, you took everything from me...but mark my words. You will meet your end at the hands of Arlong the Saw!"