AN: Hello everybody!

Welcome to my first ever fanfiction to be published on this site! And it's... a ship fic between Mario and Sonic?

Yeah... I'm aware that's a little weird, but I honestly haven't seen too many fics about these two floating around. (Gee, maybe there's a reason for that, Steel) I could be here for hours talking about what possessed me to write this, but you guys came here to read a fanfiction, so that's what you're gonna get! All I ask for you guys going into this is to not take this too seriously, and no I don't ship this seriously, this is just something I'm writing thanks to a dumb headcanon that wouldn't go away. Also, something I should probably mention is that this could also be considered a crossover with Mario & Sonic at the Olympic Games, considering quite a few chapters take place during them.

And with that out of the way, enjoy I suppose?

07/08/17 Edit: Thank you for over 100 reviews! I appreciate every single one of you who took time out of your day to leave a few words, it really means a lot to me. :)

~From Rivalry to Romance~

/~/

~Chapter One: Welcome to the Smash Mansion!~

The bus slowly made it's way up the gravel road, small pebbles crunching as the tires ran over them and the whole bus occasionally jumping thanks to random potholes in the ground. Sonic the Hedgehog - currently the buses only passenger - gripped the edge of the seat tighter as the bus lurched again, flicking his ears in annoyance before resuming what he'd been doing for the past twenty minutes, staring out the window longingly. With how fast he naturally was, Sonic probably could have made it to the fabled 'Smash Mansion' and back fifty times by this point, but according to the rules all competitors must arrive by bus. And while Sonic wanted to protest against such an outlandish rule, he kept his mouth shut and took the very slow transportation method out of the fear that he could possibly get disqualified. After all, he wanted to leave the rest of the fighters with a good first impression, and acting like a child was not the way to do it.

The bus driver - an anthropomorphic turtle who went by the name of Kapp'n - ceased his whistling and glanced in his rear-view mirror at Sonic, clearly wanting to start a conversation with his passenger.

"So yer a new face," Kapp'n noted, his voice raspy. "I recognize yer species, but I've never dropped off one of yer kind 'ere before though."

"That really doesn't surprise me," Sonic casually stated, lacing his hands behind his head.

"It would appear that ye need to be a top-form fighter to be invited 'ere," Kapp'n continued. "So I'm assuming ye fit that description?"

Sonic only shrugged. "I guess, considerin' I am a so-called hero."

"Several heroes have gathered 'ere," Kapp'n explained. "Even the most famed of them all, Mario!"

At the mention of his name, Sonic's quills bristled and his lips curled into a snarl, his blood rising in temperature. He wasn't sure why, but at some point people had begun comparing the two together, causing the two of them to develop a mutual hatred of each other thanks to how often the other was brought up whenever they pulled off some amazing heroic stunt. It was that reason alone why Sonic was shocked that he was even on this bus in the first place, since he was the apparent leader of all the fighters here. Sonic had managed to come up with two theories though, either he wanted to put their rivalry to rest and try and become friends, or he really wanted to beat him up on the battlefield. And since Sonic was highly skeptical of the former option, he decided that the latter was the most obvious case.

No matter though. Even if they still hated each other by the end of this tournament, nothing was stopping Sonic from making friends with some of the other fighters, right?

Sonic had become so lost in his thoughts that he barely registered that the bus was beginning to slow, finally stopping at the end of a long brick path. The lack of movement jolted Sonic out of his thoughts, and blinking once quickly stood and stretched, before grabbing his bags and making his way to the front of the bus.

"Thanks!" Sonic called to Kapp'n as he stepped off of the bus into the fresh outside air, happy with that fact that he was no longer restrained to such a small space.

"Yer welcome!" Kapp'n called back. "Good luck in the tournament laddie!"

With that the bus began to pull away, and Sonic took a deep breath before he took in the sights around him. Flowerbeds ran the length of the path, which led to a pavilion with a large fountain in it's center surrounded by a few brass benches. It was nothing compared to the main attraction itself though, the mansion was the largest building Sonic had ever seen in his life. Ivy hung from the rooftop, but it only added to the grandeur of the sight. From behind the mansion Sonic could make out the pointed tops of roofs, and he wondered what those buildings could possibly be for since the mansion was so huge.

But the best part - in Sonic's personal opinion of course - was the large amount of room to run.

Sonic quirked an eyeridge and folded his arms, impressed. He certainly hadn't expected the mansion to be as fancy as it was, and this was only the sight from the pathway. Who knew what other secrets the mansion could be hiding? Closing his eyes, Sonic inhaled the fresh, clean air and felt the wind ruffle his quills. Only a moment later, he opened his eyes and frowned, having felt something odd in the wind. It was unnatural almost, and while it took away from the perfect paradise vibe he'd initially gotten, he shrugged it off as he ascended the steps and stood in front of the door.

Well, this was it. This was his life for the next approximate year, as he'd been told that time did not flow in this gap between the dimensions, almost like they'd all been put into stasis. And while it slightly unnerved Sonic that when he got home his friends would be older while he wouldn't have aged a day, he once again pushed that thought out of his head and knocked on the door, smoothing down his quills so he looked presentable to whoever answered the door.

If anyone would answer the door, that was.

Annoyed, Sonic knocked again - louder this time. For a mansion with over thirty fighters, no one felt the need to stay near the door in case anyone else showed up? After a few more moments of waiting Sonic rolled his eyes and was about to go look for an open window or unlocked back door to go through when he heard the lock click and a voice say, "Yeah, yeah, gimme a minute here..."

A few seconds later the door opened, Sonic being somewhat taken aback by the giant floating hand that resided in the doorway, fingers twitching erratically.

"Whazzup!?" the hand greeted in a booming, crazy sounding voice.

Blinking, Sonic recovered from the shock and rummaged around in one of his bags for his invitation. "Uh, I'm Sonic the Hedgehog, an' I'm here for the Super Smash Brothers tournament..."

The hand stared at the invitation for a moment before snapping his fingers and floating aside in order to let Sonic in.

"Yeah, yeah, right! You're the last one to show up actually, everyone else is already here! I'm Crazy Hand, the brother of the guy that runs the tournament, his name's Master Hand."

"The last fighter to show up, huh?" Sonic asked somewhat skeptically. Normally he would have believed Crazy Hand - he knew he was late showing up - but right now the mansion was quiet. Too quiet. If he was the last one to show up, where was everyone else?

"So, where is everyone?" Sonic asked. Crazy Hand pointed up towards the roof.

"Come check this out, it's like, super weird."

Curiosity now piqued, Sonic followed Crazy through the halls of the mansion, taking in the sights around him. The mansion was just as fancy on the inside as it was on the outside, and the amount of rooms seemed endless. Sonic knew he was going to have fun exploring every corner of every room, but right now that thought got pushed to the back of his mind as Crazy led him up three flights of stairs and to a simple looking door labelled 'ROOF'.

"It's through here," Crazy explained, opening the door and leading them both out onto the flat roof of the mansion, which was mostly barren save a few wooden crates with labels such as 'Assist Trophies' and 'Banana Peels' stacked in a corner. Sonic would have examined the crates a bit more, if it wasn't for the cold air that caught his attention. He didn't even need Crazy to point out what he was looking for, he could already see it himself.

And in all honesty, it frightened him somewhat.

Giant purple voids dotted the sky in the distance and the wind blew again, but not the wind Sonic loved that pushed him towards his next adventure. This wind felt dead, and chilled Sonic right to the bone when it blew past him.

"What are those?" Sonic questioned, and Crazy began to speak a mile a minute.

"I dunno, they just started showing up today. My brothers in there, along with the rest of the fighters. They've taken to callin' it 'Subspace' it seems."

"Hmmm," Sonic folded his arms and put his head down, deep in thought. When he finally looked up again, there was a spark in his eyes that hadn't been there before. "I'm goin' in there." Sonic announced, taking Crazy by surprise.

"WHAAAAT, but no one's come back after they went in, for all we know they could'a DIED in there!"

"They might need my help," Sonic explained, getting ready to leap from the rooftop. "An' I haven't had the thrill of an adventure in a while, should be pretty fun." He shot a playful wink at Crazy, before hurdling himself over the roof; curling into a spindash to break his fall before tearing across the ground, eyes set on the largest of the voids, what he only could assume was the entrance to Subspace.

He only hoped he wasn't too late.