When Slimes Collide │ Rimuru Tempest [Part 1/?]
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The afternoon sun filtered through the canopy of the Jura Forest as Rimuru Tempest bounced along the familiar path toward home. His three-day diplomatic trip to the neighbouring nation had been exhausting but productive, filled with negotiations, formal dinners, and endless pleasantries that came with being the Chancellor of the Jura Tempest Federation. Now, in his natural slime form, he relished the freedom of movement, the wind rushing past his gelatinous body as he hopped from branch to branch.
Almost home, He thought contentedly, his internal voice echoing within his consciousness. I wonder what everyone's been up to while I was gone. Knowing Shion, she's probably prepared some kind of 'welcome back' feast...
The thought made him shudder slightly, his blue form wobbling with the motion. Shion's cooking was... an acquired taste. One that he had not yet acquired, despite his best efforts.
As Rimuru bounded through a particularly dense section of forest, something caught his attention—a dark opening partially concealed by hanging vines and overgrown roots. The entrance to a cave, and one he didn't recall ever seeing before despite his many travels through these woods.
"Hm?" Great Sage's voice resonated in his mind. "Notice: Magical energy signatures detected emanating from the cave structure ahead. Analysis suggests the presence of rare mineral deposits."
Rimuru paused mid-bounce, hovering in the air for a moment before landing softly on the forest floor. His curiosity, that insatiable trait that had gotten him into trouble more times than he could count, flared to life.
Rare minerals, you say? Well... I suppose a quick look wouldn't hurt. I'm already running late anyway, and what's another hour or so?
"Answer: Your subordinates are expecting your return at sunset. Current trajectory suggests you would arrive approximately thirty-seven minutes ahead of schedule."
See? Plenty of time!
Without further hesitation, Rimuru bounced toward the cave entrance, slipping easily through the vines. The interior was cool and damp, the air thick with the scent of earth and stone. As his gelatinous form adjusted to the darkness, he noticed the faint glimmer of ore deposits embedded in the walls—veins of copper, traces of iron, and something that sparkled with an otherworldly blue light.
Ooh, shiny!
Rimuru approached the glowing ore, his slime body extending a pseudopod to touch it. The moment he made contact, his instincts took over.
"Predator activated. Analyzing: Magistone ore detected. Rare mineral with high magical conductivity. Proceed with absorption?"
Obviously!
His body enveloped the chunk of ore, pulling it into his stomach dimension where it was quickly broken down and analyzed. The rush of information flooded his consciousness—the mineral's composition, its properties, potential applications. It was like solving a puzzle, each new piece of knowledge fitting perfectly into place.
Energized by his discovery, Rimuru bounced deeper into the cave, his form practically glowing with excitement. He devoured ore after ore—chunks of mythril, deposits of adamantite, even some rare orichalcum that made Great Sage practically buzz with analytical fervor.
The cave system wound deeper and deeper, the passages growing wider and more elaborate. Stalactites hung from the ceiling like stone fangs, and the sound of dripping water echoed in the distance. The magical energy in the air grew stronger with each meter he traveled, a subtle pressure that would have been uncomfortable if he still had lungs to breathe with.
After what felt like hours of exploration and enthusiastic consumption, Rimuru rounded a corner and froze.
The passage opened into a vast underground chamber, easily the size of a cathedral. But what caught his attention wasn't the impressive geology or the veins of precious ore that ran through the walls like golden rivers. No, what made him stop completely was the lake.
It dominated the center of the cavern, its surface perfectly still and reflecting the bioluminescent fungi that clung to the ceiling above, creating an ethereal blue-green glow throughout the space. The water was so clear he could see straight to the bottom, where more precious stones and minerals glittered invitingly.
Wow, Rimuru thought, momentarily forgetting his ore-hunting in favor of admiring the natural beauty. This is incredible. I had no idea something like this existed so close to Tempest.
He bounced closer to the water's edge, ready to perhaps take a sample or investigate the mineral deposits below, when something moved.
At first, he thought it was just a trick of the light, a reflection distorted by a ripple in the water. But then he saw it again—a shape, roughly spherical, translucent and gleaming with an opalescent sheen that shifted between pale blue and soft violet as it moved.
Another slime.
But not just any slime. Even from this distance, Rimuru could sense something different about it. There was an intelligence to its movements, a purposefulness that reminded him of... well, himself.
The other slime surfaced fully, emerging from the lake with a grace that seemed almost practiced. It was slightly smaller than Rimuru, its body a beautiful gradient of blues and purples that seemed to shimmer with internal light. As it settled on the shore opposite him, Rimuru noticed something else—the magical energy radiating from it was immense, far beyond what any normal slime should possess.
For a long moment, neither of them moved. The cave fell into absolute silence, broken only by the occasional drip of water from the stalactites above. Two slimes, separated by a underground lake, staring at each other across the impossible distance.
Then, simultaneously, they both seemed to realize the same thing.
Wait... is that slime... aware?
Is that slime... like me?!
The shock of recognition hit Rimuru like a physical force. In all his time in this world, he had never encountered another sentient slime. He'd met plenty of regular slimes, of course—mindless blobs that operated on pure instinct—but this was different. This slime was looking at him with what could only be described as conscious thought.
The surprise was so overwhelming that Rimuru's concentration shattered. His carefully maintained slime form rippled and collapsed, and before he could stop it, he found himself transforming. Light enveloped his gelatinous body as it restructured, limbs forming, features solidifying, until he stood on two legs in his human form—a somewhat androgynous figure with blue hair and golden eyes, dressed in his usual black jacket with gold trim.
"Ah—!" He started to exclaim, raising his hands in a placating gesture.
But he never finished the sentence, because at the exact same moment, the other slime had undergone an identical transformation.
Where there had been a shimmering blob of blue and purple, there now stood a young woman.
She was slightly shorter than Rimuru, with an ethereal beauty that seemed almost otherworldly. Her hair was long and flowing, a cascade of pale blue that darkened to deeper navy at the tips, falling past her shoulders in gentle waves. Her eyes were a striking amber-gold, sharp and analytical as they fixed on Rimuru with an intensity that made him feel uncomfortably scrutinized. She wore an elegant outfit that reminded him vaguely of Chinese-inspired robes—A sleeveless white top with gold accents and a high collar, paired with a blue skirt that fell to her knees. Detached sleeves covered her arms, and the whole ensemble had an air of sophisticated practicality.
But what really caught Rimuru's attention was her expression. Where he was openly shocked, mouth slightly agape and eyes wide, she appeared calm—almost eerily so. Her face was a mask of composed serenity, with only the slightest widening of her eyes betraying any surprise at all.
The silence stretched between them, heavy with unspoken questions and mutual astonishment.
Finally, Rimuru found his voice. "You... you're a slime too, aren't you?"
The young woman tilted her head slightly, studying him with those penetrating golden eyes. When she spoke, her voice was soft but clear, with a measured quality that suggested every word was carefully considered.
"I am," She replied simply. "And you are as well. An evolved slime, from what I can observe. Though..." Her gaze travelled over him analytically, "your energy signature is unusual. There's something different about you. Something that suggests you weren't always as you are now."
Rimuru blinked in surprise. She could tell that much just from looking at him? "That's... pretty perceptive. Yeah, I'm actually a reincarnated human. Well, I was a human in my past life, anyway. Now I'm... this." He gestured at himself somewhat awkwardly.
"I see." The woman's expression didn't change, but there was a flicker of something in her eyes—curiosity, perhaps? "That would explain the anomaly. I am a pure slime, evolved through natural means rather than reincarnation."
"A pure slime?" Rimuru stepped closer, his own curiosity overriding his surprise. He walked around the edge of the lake, closing the distance between them. "But you're clearly sentient. Self-aware. How did that happen? I've never met another slime like that who wasn't reincarnated or named by someone powerful."
The woman watched his approach with that same calm demeanor, not retreating but maintaining a measured distance. "Time," She said simply. "Magical absorption. Evolution. I have existed in these caves for longer than I can accurately recall. Decades, certainly. Perhaps centuries. When you consume enough magic, absorb enough knowledge from the unfortunate adventurers who stumble into your territory, consciousness emerges naturally."
"Centuries?" Rimuru's eyes widened. "You've been alone down here for centuries?"
"Alone is a relative term." Her gaze drifted to the glowing fungi on the ceiling. "There are creatures in these depths. Monsters, mimics, the occasional foolish treasure hunter. I have had... company, in a manner of speaking."
There was something in the way she said it—so matter-of-fact, so devoid of emotion—that made Rimuru's heart ache. He knew loneliness. Even with all his friends and subordinates in Tempest, he sometimes felt the isolation of being different, of being the only one who remembered a world of smartphones and convenience stores. But this woman had experienced something far worse—centuries of solitude in the dark.
"What's your name?" He asked gently.
She blinked, as if the question had caught her off guard. "Name? I..." She paused, a slight furrow appearing between her brows—the first real expression of uncertainty he'd seen from her. "I do not have one. Names are given, are they not? There has been no one to give me such a thing."
"Then how do you think of yourself?"
"I simply... am." She looked down at her hands, turning them over as if seeing them for the first time. "I exist. I hunt. I collect magic. I study. The concept of a name is... foreign."
Rimuru felt his chest tighten. A being of such obvious power and intelligence, who had lived for so long, and yet she didn't even have a name. It was wrong somehow, fundamentally wrong.
"Would you like one?" He asked impulsively. "A name, I mean?"
Those amber eyes snapped to his face, sharp and assessing. "Can you grant names? You possess sufficient magical energy, certainly, but the act of naming requires—"
"Yeah, I can name you," Rimuru interrupted, a slight smile crossing his face. "I've named quite a few individuals actually. It's kind of become my thing. Though I should warn you, it takes a lot of magical energy, and you might feel pretty tired afterward."
The woman was silent for a long moment, her gaze never leaving his face. He could practically see the calculations running behind those golden eyes, weighing risks and benefits, analyzing his intentions.
"Why?" She finally asked. "Why would you offer this to a stranger? You know nothing of me. I could be dangerous. Hostile."
"Are you?" Rimuru countered. "Dangerous and hostile, I mean?"
"I could be."
"But are you? Right now, to me?"
Another pause. Then, almost reluctantly, "No. You have shown no aggression. You possess no treasure I desire. There is no logical reason to view you as a threat or target."
"Well then." Rimuru's smile widened. "I'm offering because everyone deserves a name. Because names have power and meaning. And because..." He rubbed the back of his neck sheepishly, "I kind of feel like we're the same, you and me. Slimes who became something more. That's pretty rare, and I think that makes us... I don't know, kindred spirits maybe?"
The woman studied him for another long moment, and then, to his surprise, her lips curved ever so slightly—not quite a smile, but close. It transformed her face, softening the cold analytical mask she wore.
"Very well," She said quietly. "I accept your offer, strange slime who was once human."
"Rimuru," He corrected. "My name is Rimuru Tempest. And before I name you, I should probably know more about you. What are you good at? What do you like? What defines you?"
The woman—still nameless for a few more moments—considered the question with the same careful thought she seemed to apply to everything.
"I am a mage," She said finally. "Magic is my purpose, my passion. I collect spells the way some collect treasures. I have devoured grimoires, absorbed the knowledge of deceased magicians, analysed the spell structures of every creature I have encountered." Her eyes brightened slightly, the first real show of enthusiasm he'd seen from her. "I possess thousands of spells in my repertoire. Offensive magic, defensive barriers, elemental manipulation, spatial distortion, temporal magic, summoning circles, curse techniques, holy enchantments..."
She continued listing magical disciplines, her voice growing incrementally more animated with each category. Rimuru listened, both impressed and slightly overwhelmed. This woman wasn't just a mage—she was a walking magical encyclopedia.
"—and I have recently been studying the theoretical applications of combining multiple magical systems into singular casting frameworks, though the energy requirements are substantial and the risk of catastrophic failure is—" She stopped abruptly, seeming to realize she had been talking continuously for several minutes. A faint flush colored her pale cheeks. "I apologize. I became... carried away."
"Don't apologize!" Rimuru laughed. "That was amazing! I've never met anyone so passionate about magic. Well, except maybe Ramiris, but she's a whole different category of magical obsession." He tapped his chin thoughtfully. "A collector of spells, huh? Someone who hunts knowledge and magic with dedication and precision. Someone who's intelligent, powerful, and just a little eccentric..."
He thought about her appearance—the blue hair that reminded him of water and sky, the calm demeanor that concealed fierce passion, the graceful way she moved. He thought about her essence, the centuries of magical accumulation, the refined intelligence.
"How about [Y/n]?" he suggested. "It means 'your name'—kind of meta, I know, but I think it fits. You get to define who you are, what you become. The name is a beginning, not a limitation."
The woman—[Y/n]—tested the name silently, her lips forming the sounds without voice. Then she nodded, once, decisively.
"[Y/n]," She repeated aloud. "Yes. I find this acceptable."
"Great! Okay, this might feel a little weird, but try not to panic." Rimuru stepped closer, raising his hand. "[Y/n], I name you as my equal, as a fellow slime who has reached heights beyond the ordinary. Take this name and make it your own!"
The magical energy that flowed from Rimuru was visible in the dim cave—streams of golden light that wrapped around [Y/n] like ribbons. She gasped softly, her eyes widening as the power settled into her very being, rewriting something fundamental about her existence.
For a moment, she glowed like a star, her blue hair seeming to float on an invisible wind. Then the light faded, and she swayed, her legs buckling.
Rimuru caught her before she could fall, surprised by how light she felt—though he supposed that made sense for a slime in human form. "Whoa, easy there! The naming process can be pretty draining. Just take it easy for a bit."
[Y/n] blinked up at him, her usual composure shattered by exhaustion. Her eyes were unfocused, her breathing shallow. "I... apologize for the weakness. This is... unexpected."
"It's totally normal," Rimuru assured her, carefully lowering her to sit on a smooth rock near the water's edge. "Everyone feels tired after being named. You'll recover soon, but you might need to rest for a while." He paused, noticing how her human form was beginning to flicker, becoming translucent at the edges. "Actually, you might not be able to maintain your human shape for a bit. The naming takes a lot of energy."
As if on cue, [Y/n]'s form shimmered and collapsed back into a slime—that beautiful opalescent blob of blue and purple, now seeming even more vibrant than before. She wobbled slightly, and Rimuru could sense the exhaustion radiating from her.
"Notice: Individual [Y/n] has entered a state of magical depletion. Estimated recovery time in current environment: 6-8 hours. However, recovery would be accelerated in a magically rich environment with access to additional energy sources."
Rimuru looked at the slime [Y/n], then at the dark cave around them, then back at the slime. A plan was forming in his mind—possibly a crazy plan, but when had that ever stopped him?
"Hey, [Y/n]," He said, kneeling down beside her slime form. "I know we just met and all, but how would you feel about coming back to my place? The Jura Tempest Federation, I mean. We have lots of magic users there, a really magically rich environment, and it would be way more comfortable than this cave while you recover."
The slime that was [Y/n] jiggled slightly—he was learning to read slime body language, apparently—in what might have been surprise.
"You... would invite me to your territory? We are essentially strangers."
"Well, yeah, but you're also a fellow slime, someone I just named, and honestly? I think you'd like it there. We've got a massive library, magic researchers, spell development labs... and I bet you've never had proper cooked food before, have you?"
There was a pause. Then, very quietly, "What is... 'cooked food'?"
Rimuru grinned. "Oh, you are in for a treat. Literally. Come on, what do you say? At least come visit while you recover. If you don't like it, you can always come back to your cave."
[Y/n] was silent for a long moment, and Rimuru wondered if he'd overstepped. But then she bounced once—a distinctly affirmative motion.
"Very well. I accept your invitation, Rimuru Tempest. Though I should warn you—I am not accustomed to... socializing. If I offend your companions, it is likely unintentional."
"Don't worry about it," Rimuru said cheerfully, carefully scooping up her slime form. She was surprisingly heavy for her size, and there was a strange sensation of compressed magical energy that made his hands tingle. "Most of my friends are pretty weird too. You'll fit right in."
As he cradled [Y/n] against his chest—having shifted back to his human form for easier travel—Rimuru took one last look around the beautiful underground cavern. He made a mental note of its location; this place could be valuable for the Federation, though he'd make sure to ask [Y/n]'s permission before doing anything with it.
"Ready to go?" he asked.
The slime in his arms pulsed with a soft light—agreement, he assumed.
"Then let's head home. Fair warning though, my subordinates are probably going to have a lot of questions."
The sun was beginning its descent toward the horizon, painting the sky in shades of orange and pink, when Rimuru finally emerged from the forest. He could see the walls of Tempest in the distance, the familiar sight of home making him smile despite his exhaustion.
The journey back had been slower than his trip out—carrying [Y/n] meant he couldn't just bounce along as a slime, and he'd had to stop a few times when her form became unstable from magical depletion. She'd been quiet for most of the trip, though he could sense her awareness, her consciousness taking in everything around them with that analytical intensity.
"Notice: Multiple magical signatures detected ahead. Analysis suggests a welcoming party has assembled at the main gate."
Of course they did, Rimuru thought with a mixture of fondness and exasperation. They always do.
As he approached the gate, he could make out the familiar figures of his subordinates. Benimaru stood at the forefront, his red hair catching the dying sunlight, arms crossed in his usual confident stance. Beside him, Shion was practically vibrating with excitement, her purple hair swaying as she bounced on her toes. Shuna stood with her characteristic grace, though her eyes were sharp as they scanned the forest for any sign of their master. Souei lurked in the shadows as always, while Hakurou observed with patient wisdom.
And there, weaving between everyone's legs with chaotic energy, was Ranga in his wolf form, tail wagging so hard his entire back half seemed to be moving with it.
"Lord Rimuru!" Shion's voice carried across the distance, loud and enthusiastic. "Welcome back!"
Rimuru raised his free hand in greeting, very aware of the curious glances being directed at what he was carrying. As he reached the gate, the questions started immediately.
"Lord Rimuru," Benimaru stepped forward, his eyes dropping to the slime cradled in Rimuru's arms. "Your journey was successful, I trust? And your... companion?"
"Master!" Ranga bounded forward, transforming mid-leap into his smaller, more manageable form. "You've returned! But who—what—there's another slime? And it feels so powerful!"
Shuna approached more carefully, her analytical gaze taking in every detail of [Y/n]'s form. "Rimuru-sama, this slime's magical energy is extraordinary. Where did you encounter such a being?"
"Is that dinner?" Shion asked brightly, leaning in for a closer look. "It's very pretty! What does it taste like?"
"NO!" Rimuru practically shouted, unconsciously tightening his hold on [Y/n] protectively. "This is absolutely not dinner! This is [Y/n], she's... well, she's like me. Another sentient slime."
The declaration caused an immediate stir among the gathered subordinates. Benimaru's eyebrows rose to his hairline. Shuna's eyes widened. Hakurou stroked his beard thoughtfully. Even Souei emerged fully from the shadows, his usually impassive face showing distinct interest.
"Another sentient slime?" Benimaru repeated. "In all my years, I have never heard of such a thing, save for yourself, Lord Rimuru."
"Yeah, well, there's a first time for everything." Rimuru shifted [Y/n] slightly in his arms. "I found her in a cave system about an hour's journey from here. She's been living there for... actually, I'm not entirely sure how long. A really long time."
"And you named her," Shuna observed, because of course she would pick up on that detail immediately. The slight depletion in Rimuru's own magical energy would be obvious to someone as skilled as her.
"I did," Rimuru confirmed. "Which is why she's currently in this state. Naming takes a lot of energy, and she's still recovering. I was hoping we could set her up somewhere comfortable to rest. Maybe one of the guest rooms near my quarters?"
"Of course, Rimuru-sama." Shuna immediately shifted into organization mode. "I'll prepare the room personally. Shion, please fetch some of the magical crystals from storage—they'll help accelerate recovery. Benimaru, inform the others of our guest's arrival. Hakurou—"
"I shall ensure the perimeter is secure," The old swordsman finished with a knowing smile. "Though I suspect this guest poses no threat."
"Actually," Rimuru interjected, "I'm not entirely sure about that last part. [Y/n] is... well, she's incredibly powerful. She's collected magic for centuries, and from what she told me, she's got thousands of spells at her disposal. She's just too tired to be a threat right now."
This revelation caused another stir. Souei's hand drifted toward his weapon almost unconsciously before he caught himself.
"Centuries of magical accumulation?" Shuna breathed. "That would make her one of the most powerful mages in existence. Rimuru-sama, do you trust her?"
It was a fair question, and one Rimuru had been asking himself during the journey home. But when he looked down at the slime in his arms—at [Y/n], who had accepted his offer of friendship despite having every reason to be suspicious, who had been alone for so long she didn't even have a name—he found his answer came easily.
"Yeah," He said simply. "I do. She's a bit... intense about magic, and definitely not great with emotions or social stuff, but she's not malicious. Just lonely, I think."
Shuna's expression softened at that. "Then we shall ensure she feels welcome. Come, let's get her settled."
The group moved through the streets of Tempest as the evening deepened. Residents paused in their activities to wave at Rimuru, their lord and founder, though many cast curious glances at his unusual cargo. Word would spread quickly—it always did in Tempest—but Rimuru wasn't worried. His people were used to unusual circumstances by now.
The guest room Shuna prepared was on the same floor as Rimuru's quarters, spacious and comfortable with a large bed, a desk near the window, and bookshelves that Shuna quickly filled with various texts on magical theory. She even added a small table with a bowl of magical crystals, their soft glow providing both light and a source of energy for recovery.
"This should suffice for now," Shuna said, stepping back to survey her work. "Though if she requires anything else once she wakes, please let me know immediately."
"Thanks, Shuna. You're the best." Rimuru carefully placed [Y/n]'s slime form on the bed, where she immediately settled into the soft pillows with what could only be described as a content wobble.
As the others filed out, leaving Rimuru alone with his unexpected guest, he pulled up a chair beside the bed and watched the gentle rise and fall of her gelatinous form—the slime equivalent of breathing, he supposed.
"You're going to like it here," He said quietly. "It might take some getting used to, and everyone's going to be really curious about you, but I think you'll find it's better than being alone in a cave. At least, I hope you will."
[Y/n]'s form pulsed softly, and though she didn't speak, Rimuru got the sense she was listening.
He stayed there for a while longer, keeping watch over the first being he'd met who truly understood what it meant to be a slime who was more than just a slime. Outside, the sounds of Tempest settling in for the evening drifted through the window—laughter, conversation, the daily life of a thriving community.
Tomorrow would bring questions, introductions, and probably no small amount of chaos. But for now, in this quiet moment, Rimuru was content to simply sit and be grateful for the strange twist of fate that had led him to that cave.
After all, in a world of magic and monsters, reincarnation and evolution, what was one more impossibility among friends?
