A young woman was standing in the middle of a large building, blasters samples ranging in the walls, mecha beast samples on the entrance hall, just some basic models with no customisation, enough to let someone test it out, and, of course, a whole circuit of glass pipes with around the walls and ceilings.

Two small strange creatures could be seen on her shoulders. 

On one shoulder was one orange in color with a pair of cute horns, and on the other was a purple one with a cobra-like hood in the other.

"Today is the big day!" She said, full of energy.

The purple creature chirped something with a sullen look, but the other one just snarled quietly.

"I know, I know" Said the woman "Anyway, it's time to open!"

The orange one rolled its eyes, jumping on her hood, while the purple one rolled her eyes with amusement.

Today was a big day.

Today was a wonderful day.

***

Today was a terrible day.

She had just got kicked out of her party for no reason, just saying they had no use for someone like her, being replaced for some random girl they found.

It was ok if it was just that, since she quickly managed to find another party, but things got worse.

Her party ditched her in the middle of a mission when they tried to fight some Demonic Beasts that they obviously couldn't defeat and stole most of her things.

Now Melody had lost herself on the way back to the city, left to fight alone in less than favorable circumstances.

Such as little ammunition for her gun.

She was a Magic Musketeer, so she did carry a sword with her, but she couldn't keep moving recklessly and was wasting energy and mana.

To her luck, she started to encounter less and less Demonic Beasts, but that was it.

She was so stressed and overwhelmed by the situation that, the moment she saw a clearly human building, she ran to it without a second thought.

She noticed how big it was, looking more like a store than a house, along with the strange logo-thing in the front, but she didn't care much, not even registering the name.

If someone had the guts to build a store outside the city, then they must have the means to protect it.

She saw the 'Open' sight in the door and pushed it over with a sigh of relief as she entered at the sound of a bell.

Just to freeze when she saw what was inside.

Strange guns could be ranging in the walls, and animal-looking metal statues(?) were scattered around, not moving, a strange circuit of glass pipes all around the place and a counter was also visible on the other side of the store.

She approached one of the animal-looking-thing, analyzing it, noticing its strange structure, like the motorcycle handles on its backs.

It was a strange place, and the silence was leaving her nervous.

"What the-" 

"Hello?"

She jumped in surprise, then bolted in the voice's direction.

A woman, at best twenty, with bizarrely pale skin and really short deep dark green hair and acid green eyes appeared.

She wore a white crop top hoodie, leaving her black shirt exposed, she also wore baggy pants of the the same color of her hair, only anklets covered her feet and a penny bag on her torso and a strange belt on her waist with strange blue cylinders

But that wasn't the most interesting thing about her, no.

What caught Melody's attention on the woman was the strange creatures on her shoulder.

They were small, and strangely cute in some way, with their big eyes and strange appearance.

The woman approached Melody with a large and energetic smile and, much to her surprise, she had some good fangs.

"Welcome!" Said the woman "Did the Mecha Beast catch your interest?"

So this is what it was called, quite the name for it.

"Kind of?" She said "I just came here looking for some safe place to stay a little and saw it when I came in"

The woman nodded, understanding, the purple creature on her shoulder did the same, but the orange one narrowed its eyes at her.

"What is that?" She finally asked.

The woman paused, a bit embarrassed for a second, but soon recovered, using her finger to pet the purple one while explaining.

"I'm sorry for my lack of manners" She said "It's been a while since I'v talked with anyone other then the slugs and… friends"

The last part seemed a bit unsure, but Melody didn't comment, more focused on the extended hand.

"I'm Shaun" She said before pointing to the purple "This girl here is Diva, her kind is unofficially called Pieper slug, and the other one…"

She then pointed to the orange one, eyes still narrowed.

"This grumpy boy is Mirage" She clarified "He's a Thugglet slug"

Slugs?

Melody gave the creatures an odd look, the orange one, Mirage, gave her an unsurprised look as a response, while the purple one, Diva, gave her an amused look.

They're definitely not Slugs.

"I know what you are thinking" Shaun said "And yes, they are slugs, just not the conventional type"

"How come?"

Melody decided to get along with the woman, not eager to be kicked out right now.

The woman seemed eager to explain to her.

"They have abilities similar to the ones Hunters use" She said "Some can create illusions like Mirage and some can actually produce fire"

She looked at the woman for a moment, then at the 'slug', who returned the look, still unsurprised.

"Illusions?" She said.

Her tone must have given her away since Mirage growled at her, chirping angrily.

"They might not look much" Said Shaun "But I can guarantee their abilities! They're the reason this place exists!"

That brought Melody's attention, as she was starting to question what kind of place was that.

And the woman seemed to notice this.

"Well" She started, opening her arms with a large smile "Sorry for the late introduction, but welcome to the Ninety Nine Caverns, here you can find Mecha Beasts, Blasters and slugs of all kinds! And today is your lucky day since it's our opening day! What may I help you with today, dear customer?"

Diva chirped, obviously amused at the situation, but Mirage just humbled something while rolling his eyes.

Melody more confused them ever, not at all expecting this place to be a store.

Maybe some eccentric noble of some kind who decided that the city was too boring to leave.

But a store?

Unbelievable.

"Sooo… you sell this… things?" She said pointing at the Mecha Beast at her side.

But who was her to judge?

She needed shelter.

And the eccentric noble theory was still standing.

"Yep!" Was her answer "These guys are practical means of locomotion since, depending on the type, terrain is not of much importance, wanna try?"

Not really, but not like she had a choice.

She quickly jumped in the back of the one she was close to, a feline one.

With a swift movement, the Mecha Beast activated after some quick instructions.

"Now try to walk" Said Shaun.

And so she did.

It was pretty easy to operate, and even though it was strange to walk on it, it wasn't bad.

It was actually really smooth? Feels better and more stable than using a beast.

She even tried out a bull-looking one that Shaun said was good for heavy load transport, and was satisfied, even though it wasn't her style.

There are Beasts used for transportation, but they're hard to train and really expensive to keep. She rode one before, it made her sick. 

To say she was surprised was an understatement.

She tried, with Shaun's help, a few more movements, like a bit of running, jumping and sudden turns, and it was surprisingly good, as well as some other Mechas, still preferring the feline one.

And, best bart, all of them have diferente mods.

Shaun at some point, guided her to a deeper part of the store, in a place she called Testing Grounds 1, with a motocross track, and later to the Testing Grounds 2, with a pool with waves simulator.

There she finally saw the other modes the Mecha Beast had.

And it was delightful to say the last.

With a wheeled mode and one that moved above water, it was practically a perfect mount.

With such a practical and useful vehicle, she would most definitely spare many transportation expenses, even better, as it was a machine, it didn't need to eat or would get tired, so less need to spend more or take breaks during a mission.

But the thing is…

The Mecha itself was expensive.

"One high-grade core!?"

They had come back to the counter, Melody was thinking in buying one of the feline model for her in hope to have a pratical.and realible tronsportation back to the city, whe she recived the news.

She wouldn't be surprised if it was expensive. God! She would be surprised if it wasn't!

But it didn't cost money, as she expected, but cores.

And a high-grade one at that!

To get one of these a hunter had to fight a high-grade monster!

She actually could pay, as she used to be part of a high-grade party, but it was still shocking.

Shaun and her 'slugs' didn't seem affected by her outburst, much on the contrary, they seem to expect that.

For God's sake, Mirage was snickering at her!

"Expensive, I know" She said "But actually you are paying not only for the Mecha, but also for it's core"

Shaun approached the Mecha and, with a swift moviment, she opened it, revealing a blue glowing sphere inside it,

"Mechas can only move there is slug energy" She explained "And it can only be founded in slugs, who produces that energy naturaly, it takes time and patience to concentrate it into a core that, without slugs around to sustain it, will slowly start to die out, like a heart without blood, so it would be recommended to have a Fandango slug with you, as they are the biggest energy producer among the slugs"

Again, the slugs.

She was starting to get suspicious of all this.

Seeming to notice this, Shaun smiled.

"What about I properly introduce the slugs for you?" She asks before gesturing to the walls "Chose a blaster, you'll need it"

Melody hesitated a little, wondering how these strange looking guns could help Shaun in explaining all of this.

But she did as she was told, curious about the explanation.

She walked to the nearby wall, looking at the 'blasters' one by one, also noticed that the pipes she saw earlier had wind coming out of them through a few exits.

They all had that strange blue cilinder on them, the same one that she saw on Shaun's waist.

After looking for a while, she saw one that brought her attention.

It was a long one, diferente from the others, it had many cylinders on it and seemed to be heavy.

She grabbed that one, trying out the weight and holding it into a firing position.

It was a bit heavy, but not that much, much tk her surprise, and it felt good to hold, so she choosed that one.

She was about to turn back when something moving caught her atencion.

In one of the pipes, a bunch of blurs moved fast and got out of one of the exits.

It was another 'slug', three of them actually, one had two shades of blue and yellow details that reminded her of lightning bolts, the other was red and beige with a pair of blue horns and the last was purple one with many eyes.

They looked around with disinterest before their eyes paused on her.

For a few seconds, they stared at each other, eyes wide open, not knowing what to do.

Bit then it moved first.

A big smile appeared on their faces, all three of them chirping with weird cries.

She was a little surprised by the reaction, but also a bit amused.

She waved a hand to the pair, turning to return to the counter with the blaster on her sholder, not noticing how they both froze as she did.

She returned to the counter, where Shaun was waiting for her.

"Oh! You got a Sharpslinger Lightningbolt XD" She said excitedly "This one is good for sharpshooting and have a stabilizing hand grip and storage clip, the disadvantage is that you have to reload manually, unlike the Harbinger Firestorm, but is a good blaster, now should we-"

She stopped abruptly, her gaze on the blaster on Melody's shoulder, an excited smile on her face.

"Seems you're already making friends" She said.

Curious and confused, she brought the Blaster to the counter, only to see the three slugs from before, all waving at her happily.

"What-"

She looked at the slugs, then at the pippes, then back at the slugs.

How did they get there?!

"Since they're already here" Shaun said "It will be easier to explain, follow me"

Still a bit confused, she did as she was told, grabbing the blaster with the slugs and following the woman.

Said slugs who crawled from the blaster to her shoulder.

It was a strange sensation, as they were warm and light, but not repulsing, so she let them chatter on her shoulder.

They arrived at a place called Testing Grounds 3, and the place was just like a training ground, an ample and open space with dummies.

"First of all!"

Shaun stooped in the middle of the Testing Grounds, her two slugs seemed eager to see what would happen.

"Slugs are originated from the underground" She said "They have the ability to produce and radiate energy, no need to worry, this energy isn't harmful, on the contrary, it is actually much needed, as it can help the life to prolifer, I'm sure you must have seen how healthy is the flora around the factory"

Yeah, she did notice this, that's actually the reason she ended up here, as Demonic Beasts can't exist in areas full of life energy since it clashes with their demonic energy and weakens them.

But that also apply to nature, who gets weaker as time passes.

That's why, more than ever, people are fighting to preserve nature since it is their only line of defense.

And that woman said that these little guys can produce energy that helps nature grow healthily?

Unbelievable.

"And that's not all!" Said Shaun "The blaster is needed for the best part of it"

Her hand then reached for her belt, grabbing one of the cylinders and throwing it to Melody, who catched it mid-air.

"Who wants to go first?" The woman asked.

Melody was about to ask what the woman meant by that when the blue slug jumped inside the cylinder, an excited and expectant smile at its face while the other two let out disappointed growls.

It entered the same cylinder she saw on the blaster in her other hand.

She took a moment to process, eyes darting from the slug to the blaster, them to the woman.

This process repeated a few times before her gaze fixated on the woman, who was still smiling.

"Slugs can be used as ammo" She said "The blaster use the slug energy to fire them at high speed, and don't worry, it isn't bad for them, they actually love this, you just have to press the cillinder and fire, they'll do the rest"

She stared at the woman for a moment, then at the slug on her hand, it had an eager smile, using its arm-like tendons to point to the blaster excitedly.

She hesitated for a moment before doing as she was told.

She put the cylinder in place, making the empty one fall on the ground, then aimed at the dummy while holding her breath.

She then fired, letting a sigh out with the recoll that made her retreat.

The slug flyed through the training ground.

And then transformed.

It grew in size and changed its form, lightning escaping its flying form while it attacked the dummy with lightning that escaped its mouth.

When slowed down a bit, it returned to normal in mid-air and falled on top of the burned dummie, anharmed and satisfied.