“Firebrand” wasn’t his real name, of course. His mother had taken to calling him such after his mane began growing into its natural colours. The hairs bore a slight translucency, such that the mane closer to his coat appeared a darker shade than that farther out. A colorful mane like his was common among ponies with a mixed heritage; the offspring of a unicorn and an Earth pony, in particular, usually bore one of two phenotypes: a unicorn, with abnormally impotent, but not absent, magical prowess, or an Earth pony more innately in tune with the arcane. The former are almost universally seen as disabled, whereas the latter are highly regarded within Earth pony society, due to their ability to understand and interact with magic as much as most unicorns.
His nickname would prove to be more defining than anypony could have hoped, however. When he entered school, it quickly became apparent that he was, most definitely, one to spark conflict among his peers.
Much of the first years of a pony's schooling are focused on finding the students' special talents by introducing them to common fields of specialization: music, farming, crafts, and the like. It was on a camping trip that Firebrand found his own special talent. The campmaster had tasked him with starting the campfire, and was in the process of giving him instructions on how to safely do so, when Firebrand brandished a lighter—one of numerous items he'd stolen, more of curiosity than anything else, from his mother—and set the logs ablaze, nearly burning the coat off his fets in the process. The campmaster (after admonishing him and taming the blaze) noticed the newly-formed mark on Firebrand's flank: a roaring, orange and red fireball.
"Well, that's... unusual." he had said.
The expectation of a cutie mark is that it is something that can practically be incorporated into the workforce, much like the expectation that everypony will eventually get a job and be successful. So a pony with an impractical talent -- such as one for conflagration -- emblazoned on their flank is doomed to either a pathetic life doing menial jobs requiring no special talent, or a life of begging, vagabondry, or crime.
With a spark, a flame sputtered to life. Firebrand held his cherished lighter closely, letting the warmth and light keep him company. They were looking for him. He'd already been caught twice trying to start fires unsuccessfully, so once a building actually did burn down, it was natural for the townsfolk to assume he was to blame.
He was cowering in his usual hiding place: a rotted-out tree trunk on the edge of the forest. He could hear the search party, shouting after one another to find the vandalous arsonist. He wasn't worried, however; it was raining heavily, so his scent and sound should be pretty well masked from the pursuers. He only had to wait until—
"There! I see a fire!" cried a voice from nearby.
Shit. He snapped the lighter shut, pulled up his hood, and stepped out into the rain. He wore this light, hooded poncho nearly round-the-clock, to help conceal his rather conspicuous cutie mark and flamboyant mane—that it helped fend off the rain was just a happy side-effect.
A flashlight beam fell onto him. "There! After him!"
Shit shit shit. He continued running, afraid to look back. He could hear hounds baying and ponies shouting from somewhere behind him, slowly gaining on him.
Firebrand dared to look up and saw a light in the distance, barely visible through the sprawling foliage: a house? Maybe they'd help him: he could just bang on the door, and act panicked, and tell them that—
THWACK. The arsonist's train of thought was extinguished as his leg slammed into a fallen log, sending him sprawling into the mud and causing a searing pain to burn through his leg. Now is not the time to be scheming, he thought as he tried to stand up, only for his injured leg to give out under his weight. He fell again into the mud and sighed in defeat.
"Kid," said the same voice from before—coming from a nondescript brown earth stallion, looking sternly down at him—"you are in a whole world of trouble. Get up."
Firebrand looked up at the larger pony and grinned defiantly. "I can't sir." he said, wincing as he waved his wounded hoof. "My leg's broke." He wasn't sure if it was actually broken, but anything less than that would likely fall through as an excuse.
"Well, shoot." said the stallion, as he beckoned to two other ponies from the search party, just now catching up to him, to carry the wounded colt. "How 'bout this: we'll take you back to the mayor's office, and the two of you can have a nice, long chat."
"How about a hospital?" suggested the yellow colt, grinning-then-wincing again as the one of the other two ponies hoisted him onto the other's back.
“So...” started the mayor, an earth pony mare the color of dead grass. “...you like to start fires?”
“Yes’m, that’s me. Says so right here on my butt.” responded the cocky firebug, leaning back casually in the cushioned chair, “just in case the fire-instead-of-hair and the singed fets didn’t tip you off.”
"Yes, I'd noticed." the official said, leaning forward and steepling her hooves. She wore a pair of round, thin-framed glasses with thick lenses that magnified her small, pale-green irises, which seemed to be projecting spikes of solid ice as she stared at him. "I think it goes without saying that we're going to be keeping an eye on you." As she said this, she tilted her head forwards and the glasses fell slightly to the tip of her muzzle, and she continued to glare over them, her gaze almost palpable through her pinpoint irises. Interesting choice of words, thought Firebrand. I wonder if her cutie mark has to do with eyes.
"So, as long as I've got you here, Citrus, I wanted to—"
She was cut off as Firebrand leaned forward, suddenly and aggressively, slamming his uninjured front hoof against the official's desk, causing her to flinch.
"Don't call me that." His features were dead-set and serious. His voice was sober and enunciated.
The mayor leaned back slowly, slack-jawed and stunned. "Yes. Yes... is... how about 'Mr. Spark?' "
Firebrand grunted, and then leaned back, crossing his arms. She's not about to call me Firebrand, of course, but I'll burn myself alive before I let anyone call me by that damn name.
"Okay, Mr. Spark..." she began again after gathering herself. "I'd like to ask you about a few recent fires around town."
Firebrand sighed. "Am I being detained?" he asked.
"What?"
"Am I being detained?" he repeated. "Am I free to go?"
"I—this isn't a police station." said the mayor, placing her face into one of her hooves. "You're not under oath or anything. This is just off the record."
"In that case..." said Firebrand, standing up and grabbing the crutch that was leaning against the back of his chair, before turning to exit the room. "...no comment."
"I'm home." said Firebrand as he pushed his way into the small, crowded apartment. His mother likely didn't even know that he'd left, but it was still common courtesy to announce his arrival.
"Welcome back." called a voice from the other room. "Hopefully you didn't get into too much trouble. I'd hate if—" the voice cut off as its owner turned the corner and saw Firebrand with one arm in a cast, learning against a crutch. "What happened?!"
Firebrand chuckled and rubbed the back of his head with his uninjured hoof. "I tripped."
His mother's face went from a look of shock to one of bemused distrust, the sort of which a teacher gives a student when told that the dog ate their homework. She was a short, golden mare, with a small horn poking out from just below the crown of her deep red mane. Her cutie mark was an orange with a straw stuck in it, an unusual and slightly baffling mark, which signified her talent was making orange juice, a rather narrow and inapplicable talent which lead to her constantly jumping from job to unimportant job while waiting for the position of "juice mogul" to open up.
"I wish you'd be more careful." she admonished half-heartedly. "I'd hate to see you end up in the hospital some day."
"I was just in the hospital." said Firebrand, hoisting his casted arm. "That's where I got this."
His mother smirked. "Anyway, I'm about to start cooking. I'll let you know when something's ready."
"A'ight." said Firebrand, turning down the short hallway and into his room.
The room was small and dark. The walls were decorated with posters of all different kinds—bands, events, art, propaganda, all hung haphazardly and crooked. Most of the floor space was dominated by either the short, unmade bed, or the messy desk, which was covered in scraps of metal and wood, various tools, jars and tubes, and pocked with scorch marks.
He leaned the crutch against the wall and emptied the contents of his pockets—a couple of bits, a small multi-tool, and his ever-at-hoof lighter—before shrugging off his poncho, tossing it onto the floor, sitting down behind the desk, and picking up the book—Metamorphorses? some old fairy tale compendium—that was currently at the center of the workspace. He flipped it open to about halfway, and was greeted with a hollow, lined cavity carved out of the pages of the first half of the massive book. Inside of this hollow was a dense coil of insulated string, at the center of which was a small brown packet, currently empty.
Firebrand closed the book, set it aside, and prepared a metal tray with a short length of the same cord on top leading into a pile of yellow-white powder. Firebrand lifted a pair of goggles off of the wall and covered his eyes. He lit the end of the string, and the inner strands began to burn, the outer layer containing nearly all smoke and vapor as the flame made its way down the line and towards the powder. The powder was a mixture that Firebrand had been trying to fine-tune for a while now. High-heat, low smoke, more of a fizzle than a bang...
The powder disappeared in a bright flash of white light, making harsh hissing sounds, and lingering for about a second, casting off several hot sparks before fading away and leaving only the tiniest wisp of acrid white smoke. Perfect.
After cracking open the single, small window situated above his bed, Firebrand grabbed a vial full of the same yellow-white powder from the shelf above his desk, poured a measured portion of it into a small spoon, and dumped this into the waiting packet inside the book, which he then sealed before shutting the book and setting it aside.
"Firebrand!" called his mother. "Dinner's ready!"
He got up and proceeded out into the main room of the apartment—living room, dining room, and kitchen, all rolled into one. The small, square table there was stacked high with paperwork and books and ledgers from no fewer than half a dozen different companies that had offered his mother employment. A quarter of the table was cleared off, and in front of the two seats that this left uncovered were now set a steaming plate each of some kind of grilled vegetables. His mother was seated at one, already quietly eating, and Firebrand sat at the other and began to dig in wordlessly. The food was bland, but it was food. He was practically starving after the rather eventful day he'd had.
Firebrand finished his meal quickly. As he stood up to put away his plate, his mother spoke up:
"Don't forget to return that library book tomorrow."