Hi there! Here is an AU fic for the mobile game Brave Frontier by GUMI. The protagonist is a female, and not from the BF universe. She's from Earth, but she isn't a self-insert. Since the universe rules of BF are really vague, I thought it would be better to do it like this so I could introduce my interpretation of the universe, and convey it in a way that doesn't break immersion.

Oh, who am I kidding. This is just self-indulgent trashfic. I refuse to feel bad about writing this; all discussion about Brave Frontier is either metagame or waifu talk. I'm writing this for the ladies, I suppose.

Some of these lines are paraphrased from in-game dialogued; paraphrased because most of it is awkward and cringey.

Apologies for this A/N. They'll mostly be at the end of chapters, where I'll also state my headcanons for introduced characters and such.

If you had an opportunity to save the world, would you?

The expected answer was "yes," obviously. Which asshole would say, "No, I would relish in watching millions suffer and society crumble into an unrecognizable shadow of what it once was"?

It was one of those hypothetical questions people asked to fill the blank spaces of pauses in conversation, phatic expressions, not to be taken seriously. The expected response to the socially accepted "yes" was a nod or a wistful sigh, yearning for adventure (but not really, since there was a Calculus exam on Thursday).

The expected termination of this conversation was not to be flung into some mysterious vortex into a dark abyss, where a twinkling rainbow light asked for help with saving a world. She had been making a quick run to the convenience store for instant noodles and pretzels and then a mysterious voice asked her a question. Absentmindedly, she answered, and bam, she was sucked into a set of ornate monolithic gates.

I require your assistance in saving Grand Gaia, the light implored. They were soul-communing, or something, because the light had no voice. Maybe she was drugged. Maybe she had been hit by a car, or something, and was hallucinating in the last few moments of her life.

...Gaia? For the name of a mysterious fantasy world parallel to hers? How very cliché. She expected her subconscious to be a bit more creative. But then again, what kind of stick-in-the-mud would turn down such a chance, fake or not? It took a special kind of dunce to tell the all-powerful sparkle to fuck off. So she nodded in acquiescence, and before she knew it, a force sent her flying through the darkness at super-high velocity, again.

All she could hear was cold wind and all she could see was emptiness. The space between worlds was pretty desolate and depressing, she thought, before she was forced through the exit into a sunny meadow, her head hitting something hard as her vision blacked out.

"-up! Wake up!" A distant, feminine voice. The feeling of grass on her skin. A cool, refreshing breeze. Fuck saving the world, this was the life. She could lay here forever, the pale sun warming her body as she napped her days away-

"HEY! WAKE UP!"

Her eyes shot open, tranquility ruined. A girl was standing above her, her body blocking the view of the sun.

First impression: Wow, really cute. Her clothes were colorful and loose-fitting, pale blue hair flowing over her slender shoulders as she glared down, bright blue eyes darkened with irritation.

She puffed her cheeks out (adorably!). "Geez, I thought Lord Lucius sent me a dead Summoner! Not that he'd ever choose a weakling."

So the light's name was Lucius? Funny how little details like that could slip by during silly discussion about apocalypses in the synapses between universes. Well, Lucius had probably told her at one point, but she didn't pay attention. So, she had his (its? Lucius seemed neutral, but "Lord" implied masculinity) name down, but…

"Who are you?" she asked, sitting up. The girl huffed.

"I'm Tilith, Lord Lucius's advisor and your guide! I'm also a goddess!"

"…Guide?" Goddess? Goddesses were a thing? She noticed how Tilith's hair seemed to change color at the ends, depending on how the light hit it. She also noticed that she was in some meadow, with no recognizable landmarks or street signs in sight. A small crater surrounded her, presumably where Lucius had unceremoniously dumped her like the human trash she was.

…This was a lot to take in at once. For one, the grass here was greener than any grass she had ever seen in her life – it looked artificially emerald, slick with morning dew. She wondered if it would taste like spearmint if she plucked a blade out of the ground and ate it.

"You're kind of slow, aren't you? I'm your guide across Grand Gaia! You-" A rustling bush distracted Tilith from what seemed to be the beginning of a long rant, and something popped out.

It…it was… a mochi. A green tie-dyed mochi, with a darker green puffball on its head. Plump and soft-looking. She wanted to squish it.

Tilith screamed. "Eek, a monster!"

She quirked an eyebrow. "This is… a monster?" These were the things that were wrecking Grand Gaia so badly that Lucius felt the need to call on some random from another dimension to come help? She stared at it, trying to find the secrets of its devastation. The blob-thing stared back at her with shiny black eyes.

"Yo," it intoned, voice sober. Well, that sealed the deal. She was going to squeeze this stupid thing until it died, and then she was going to cuddle with its ghost until it died again. Was everything in Grand Gaia as disgustingly cute as this little guy and Tilith?

"What are you doing?!" Tilith interrupted as she started bending over to the pick the thing up.

"What does it look like I'm doing?" She was expressing herself. Haters like Tilith needed to calm themselves.

"You're a Summoner, aren't you? Summon your Units and kill it!"

Summon. Units. Yeah, okay, whatever. It was like she was dropped into a fantasy RPG all of a sudden, and instead of receiving a pleasant tutorial, she was being shamed for her lack of knowledge. See if anyone buys this game, Lucius.

"About that. How do I do that again?" And, furthermore. "Why would I want to kill something that's not even attacking me? That seems cruel."

Tilith froze, her eyes wide.

…Perhaps it was too soon to start poking holes in the faulty universe rules.

"You mean, you don't know that much…? Lord Lucius wouldn't send a complete novice to save the land, would he?"

Girl, your faith is astonishing. Lucius didn't only send a complete novice, he sent a clown as well! She wanted to exclaim. But she didn't want to explode Tilith's brain, so she tried summoning anyway. She closed her eyes, and tried to picture something taking shape. Something powerful.

It didn't work. Seriously, what the fuck was a Unit? It was one of the most painfully generic words in the world, that's what.

Uh oh, Tilith was looking at her oddly again. Come on, come on, Units. Come out so we can beat up this adorable creature and keep Tilith sane and cute.

A feeling like snap, like a thread being pulled taut, reverberated through her mind. It was alien and hard to describe. A silhouette appeared in the clearing in a flash of white light.

It was… a dude.

Say what, now? He had a mane of wild blond hair, large, scarred hands holding a gargantuan sword. He acknowledged her with solemn eyes, and nodded.

"Summoner." So she actually was a Summoner. She had done it, albeit in the most bull-shitty way ever, but no one had to know that.

"Hi," the Summoner replied, giving a little wave. Tilith relaxed.

"You summoned Warrior Eze? It seems like you have potential, after all."

The resulting fight could hardly be called a fight. One super-muscled man was no match for a lone Mossy, she learned that it was called. She felt like a complete scumbag as she watched Eze smack the creature with the flat of his sword, its body disintegrating into a white haze. It feels like I'm one of those dudes who runs a dog-fighting ring… not that Eze is a dog, but still.

When the battle was over, he nodded at her again and disappeared. The thread in her mind relaxed, and she relaxed in turn. Through the connection, she could feel Eze inside of her, innuendo be damned. His frustration when he was tackled by the Mossy, the feeling of the ground scraping his palms as he was knocked off his feet, and the ultimate satisfaction at winning the battle. The sensation of being so attuned with another made her uncomfortable, and she welcomed the termination.

Tilith seemed to have accepted the possibility that the Summoner was a newbie. When the haze that used to be the Mossy floated towards her, Tilith remarked, "Sometimes when you defeat monsters, they can choose if they'd like to join you or not as a unit. The stronger you are, the higher chance!"

From what she could parse, did this mean that Eze, who appeared human for all intents and purposes, was the same as the green blob she had just delivered the sickest of smackdowns to? The word "unit" seemed to encompass quite a lot.

The white smokiness dissipated around her and she probably breathed it in. Gross. The Summoner felt another tug as a new thread formed in her mind, and pulled on it. The Mossy appeared in her arms, unharmed.

"Sorry about that, little guy," she whispered, plucking berries from a low bush and offering them to the creature, who devoured them with gusto.

Tilith gave her an odd look. "You don't need to have Units out when you're not fighting."

"I don't mind."

She didn't relent. "The more you use your ability, the more tired you'll be, and you could really stand to treat me with more respect! I'm a goddess, you know-" Cue another rant.

The land of Grand Gaia was once prosperous, until the Gods decided to destroy humanity. At that point, humans had become powerful, and were capable of fighting back against the gods. The resulting war razed the land and made it uninhabitable, so only monsters could wander the ruins of once-glorious civilizations. Apparently, a group of deities referred to as the Four Fallen Gods have been stirring up trouble, prompting the god of the gate, Lucius, to send his closest advisor Tilith and a powerful summoner on a quest to investigate their activity.

Except for one thing. She wasn't a powerful summoner. She was an average person with average capabilities and aspirations. Who could summon, but that felt more like a lame fluke than destiny. She didn't really know what to say to Tilith. Sorry, but I'm not the hero you're looking for?

Tilith also said that summoning in itself was an ability to draw from powers of "ages past," in the form of old heroes. This made her the ghost whisperer, essentially. Spooky.

"I'll explain more to you later. Why don't you take a break?" Tilith suggested, pointing to a rustic-looking gate, ivy twining up its edges. "If you walk through there, you can go home and rest. I'll wait for you here." The goddess's orneriness melted away, and she gave the Summoner a bright smile. "We can't have our hero being tired, after all!"

Cuuute. The Summoner resisted the urge to hug Tilith to death (that maybe could be seen as psychotic) and nodded, walking through the gate.

Oh, hello darkness, my old friend. She started walking. And walking. And she walked some more.

It had to have been at least an hour. A feeling of dread welled up in her. What if she was stuck in this place forever? Tilith said that this place would lead her home, but was it really that easy?

Over time, the fear gave way to anger, mostly at Lucius. Stupid talking glitter who couldn't even pick a Summoner from this universe. Her life had been nowhere near as interesting as it was now, but at least it had been shrouded in way less darkness.

When she saw the distant pinprick of light slowly growing closer as she walked, she didn't notice that she had broken out into a run, sick of the constant abyss. It grew into the rectangular shape of a gate opening, and she rushed out-

-straight into a body.

"Sorry," she said as she helped the boy up. She hefted his lance off the ground (which was heavy! How did he carry it without breaking his back?) and handed it back to him, distracted, staring at her surroundings.

This wasn't home.

It was a civilization, which was a step up from monsters and trees. The village emanated quaintness; the scarecrow standing in the middle of a nearby field seemed to scream "I am a quaint and pleasant scarecrow, hello! :)"

But. It. Wasn't. Her. Home. Did Tilith assume that she was from this place? She felt foreign and uncomfortable, like an anomaly that shouldn't exist.

The boy was staring at her. Had he asked something?

"Hey, can you tell me where I am?" she asked faintly.

His look became more wary, like he was staring down live wire and was about to be electrocuted at any second. "You're in the Village of the Venturer in Elgaia."

Gaia. There it was again. Not home.

"Okay, I'm going to do something that might be a little crazy," she told him, looking dead serious into his eyes. They were a pretty shade of blue. "But I'm not crazy. I swear."

Not socially-defunct crazy, anyway. Her brand of insanity was just for fun, but that was beside the point.

She finally let the stress and tiredness overtake her, and started bawling.

"Alright, so you're not from this world," the boy, whose name she learned was Karl, said. "And you were pulled here by the god Lucius from your… alternate dimension…even though we have plenty of talented summoners here, in order to stop the evil plot of the Four Fallen Gods. And you have a temperamental goddess named Tilith helping you along the way." She nodded, slathering a generous amount of apricot preserve over a thick slab of sweet brown bread.

When she turned on the waterworks, Karl had stood still panicking, trying to calm her down (he had even tried giving her a piggyback ride). A nearby elderly lady had invited them in, so "the young lady could calm down." It was kind of stupid, actually. She had stumbled out of a gate, toppled a native, and started crying. Her behavior suggested that she was an escapee of an insane asylum. If she saw herself in that state, she would have avoided her because she was obviously a crazy person. She definitely would not have let her into her house, and fed her food, and maybe people were just really nice in Elgaia and this was culture shock.

"Okay, I know that this doesn't help my case much, but I'm not lying," she said, mouth full of bread. There were nuts baked into it, mmmm. She wondered if there were any chores she could do for the old lady, as thanks for her charity.

"Did you cry because you couldn't get back home?"

Wow. He hit the nail on the head.

"Yeah. I was feeling tired and frustrated, and I had just summoned for the first time. I was overloaded and I guess I just… broke, for a moment." She grinned sheepishly. "Thanks for not leaving me to rot in the street, there."

"Of course. I would never leave someone in trouble like that." He smiled, taking a sip of tea from his cup. And wow, what a smile. Was it the water they drank in this world? Is that why everyone was so good-looking? "And… I believe you. Your story is odd, but I believe you."

…Really. "Why?" she asked. Even she didn't believe that her story was true. In the "real world," she was probably lying in a pool of her own blood, speeding truck long gone, her dying brain coming up with a vivid hallucination in its attempts to stay alive.

His voice was warm. "I can tell by looking into your eyes. You're an honest, good person. If you need my help, I'll watch your back."

What.

What kind of logic was that? What kind of shounen-anime-protagonist nonsense was he spewing? Was Karl the crazy one here? Were all Elgaians this ridiculously nice and hot? Despite her incredulity, she felt better knowing she had another human ally, if he wasn't insane.

He was saying something. She should really pay attention, hmm.

"-summoning? Only summoners can walk through those gates, but you don't dress like a summoner from the Akras Summoners' Hall. You look like a civilian," he said. She looked down at her attire: a white Hello Kitty sweatshirt, black leggings, and beat-up aqua sneakers with no socks. Prime quick-run-to-the-convenience-store clothes, not so good for battle.

"It was my first time," she said. "A monster appeared, and I summoned a guy…Eze…or something. It was really weird and uncomfortable. I could feel the weight of his sword in his hands, like I was the one holding it."

Karl laughed. "I understand your discomfort. The first time I summoned a Unit, I wanted to throw up from the feeling. You get used to it, though. It's actually pretty useful because you can communicate nonverbally during battle through your connection, with time."

So Karl was a summoner, too? She noticed his armor and greaves in addition to the large, dangerous-looking lance he carried. He seemed nice and receptive to her insanity.

Hopefully he could answer her questions better than Tilith could.

"Uh, run that by me again?" She ran her hands across the cold, rocky wall, the cold iron chains attached embedded in them. There was an altar in the front of the room. "Is this a sex dungeon?"

Karl gave her a blank, questioning look. She coughed, embarrassed. "Never mind. Ignore me when I ask questions like that, please. But what do you mean by 'powering up'?"

He lit a torch, the only light source in the dank room. "In battle, you can form bonds with existing monsters as Units. I believe that you said the connection felt like strings to you," he explained, leading her to the center of the chamber. There was a circle of five smaller circles, and a sixth one in the middle, inscribed patterns ornate and beautiful.

"You can dissolve these bonds, and this will cause energy to be released. You can use this energy to power up other Units. Certain Units are very well-suited to being used in fusion."

It sounded a lot like chemistry. She nodded in understanding. She pulled on her connection with Mossy, and it appeared in her arms. "So how do I do it?"

He showed her where to put the Mossy, and where to put Eze (it felt weird commanding a fully-grown man around…). For some reason, this process required money, so she obediently threw a few golden coins onto the altar as per Karl's instructions. She lost a Mossy and gained a stronger Eze.

"If you fuse units of the same element together, you'll get more energy for your efforts and money," Karl said as they left the underground shrine. "There's more to it, like Unit types and Burst leveling, but this is all you really need to know for now. I think I have a book about it, from when I was a beginner…"

She had been too engrossed in the book Karl had given her. Tilith chewed her out thoroughly when she returned to the meadow four hours later, but she had cleared the prairie out with ease, feeling much more well-adjusted than before. Maybe she could get Eze to say more than a single sentence.

Feeling a bit better, she walked through the gate to the Village of the Venturer.

Wait. Where was she going to sleep? She had picked up some zel from the monsters she had defeated (from the people the monsters ate, the book said), but was that enough to afford a night at an inn?

…

Maybe she could bunk with that scarecrow for the night.

"Oh, there you are!" It was Karl again, waving at her from a distance. She waved back.

"Hey, Karl. I have like twenty different slimes now," she said proudly. He beamed and ruffled her hair, somehow conveying warmth through cold steel gauntlets.

"Good for you! You're on the way to being a great summoner," he said. Karl had this ability to make sentences that would be sarcastic in any context sound genuine and sweet. She grinned. "I'll give you a reward for your hard work."

Cue cheesy porn music.

She let him take her hand and followed him to another gate, this one much taller than the one she used for travel between regions. Then, he grabbed her wrist and dropped something into her open palm.

"Is this a wedding ring?" she teased.

It was not a wedding ring. It was a small pile of shiny stones that shimmered in the light. They reminded her of Tilith's hair, actually. She stared, transfixed.

"You put the Gems in the slots here," he said, gesturing to slots near the left side, "and concentrate. You can't choose who exactly you Summon, but the most powerful Units are called from this Gate. Gems are pretty rare, after all."

Rare? Why would Karl give something considered rare to someone who was essentially a stranger? She felt suspicion well up in her, conflicting with the part of her mind that insisted that Karl was probably just really nice.

"Anyways, there's been rumors of a powerful monster in the Morgan region, so the Summoner's Hall has assembled a demon slayer squad, which I'll be fighting in. I won't be back in a while, probably."

She had the impression that there was more to the story – Karl seemed young to be fighting "powerful monsters," much less fighting in a squad. She had trouble picturing the gentle boy in a violent situation at all, actually.

"Congratulations," she said, not sure what else was appropriate. "I'll miss you, though. You're my only friend here other than Tilith."

"Thanks. And don't worry. We'll be fighting on different fields, but we're fighting the same battle. Train hard, so we can bring peace to this world." His eyes crinkled in a smile, gorgeous lapis framed by long lashes, as he gave her what she assumed was a military salute and walked away.

…Wow, he was good. Her heart was fluttering and stuff. He'd make a pretty good leader, with his natural cheesiness and earnestness, she thought.

Joking aside, it would be lonely without him. Karl was the first actually friendly face she had seen here – Tilith didn't count, as she had been scowling at her when she opened her eyes. Now, she actually felt motivated to practice, fueled by friendship rather than empty doomsday talk.

She looked at the gate in front of her, and the sparkling stones in her hands. Like how Karl showed her, she fitted the five gems into the small indentations.

…

Nothing.

She stared blankly. What was she supposed to do now?

Hola, gate. Apparently I feed you gems and then you spit out a strong Unit for me. Nothing's happening right now, and it's kind of awkward. So could you be a bro, and-

In the midst of her humorous monologue, she failed to notice the gate rumbling, first faint, then reaching a crescendo as a bright light (always light, she griped. Fuck you Lucius this was absolutely somehow his fault) flashed and overtook her vision.

Then, as her sight returned, she felt weight on top of her, one strong hand clutching her wrists above her head and the other holding something sharp to her throat, gently pressing against the soft flesh of her neck and drawing a thin line of blood.

Acid-green eyes peered down at her, glinting with hostility. The bottom half of his face was covered with a black mask, but she could tell that he was scowling.

"Who the fuck are you?"

Tilith is Lucius's adviser and goddess. She's cheerful and kind, but somewhat vain. She gets wrecked in canon a lot, and has inconsistent power levels, which I'd like to change.

Eze is one of the six heroes who rose up against the gods when they launched their attack on humanity. He is taciturn and rough-around-the-edges, but polite to women.

Karl is a talented young Summoner and head of the 24th Demon slayers division. He is annoyingly good at everything. Canonically, he is childhood friends with the protagonist, but in this story, they meet for the first time at the beginning.