That Time I Got Isekai’d Again and Befriended a Slime

There is a problem with this pairing that was not immediately clear from the get-go.

You see, as no one – except perhaps Tanya – could have guessed, Mary and Shuna together made an incredibly volatile combination.

Not in their interactions. They got along quite well, actually.

The problem was in their magic.

Mary had a fairly volatile internal magicules pool all on her own. This well known by this point, and was the source of much lament for both her and her usual magic teacher, Tanya.

Her magic flow was not something that could even charitably be called smooth, and her efficiency left much to be desired on a good day. Without a medium – like her magisteel katana for instance – the channel her magic through, her ability to use it effectively sort of went to shit.

It was much better now though. Months of training hadn't been worthless, after all. And, those flashes of perfect flow and efficiency, those moments when it all just clicked… well, the damage she did to Nin Gen with a single off-balance punch was evidence enough to the sheer potential she held.

Having a larger internal pool and incredible above human power even without that magic was just the cherry on top. Really, if she could only channel her magic better. That, combined with Ability Severance, was a breathtaking level of power to behold.

If only she could channel it better within herself.

Channel it… within…

Right, getting off track.

Shuna, on the other hand, had an above average internal pool of magicules as well, along with an above average efficiency with it. Nothing quite out of this world, not yet, but certainly worth noting as it was now.

Her specialty, however, lay not in the use of magic, but rather in the alteration of magic.

This is something that would eventually be realized fully with the Unique Skill: Manufacturer after a certain monster's ascension following a certain Festival.

But she did not possess this now, and as such it was not the focus.

The focus was – and the main issue that arose when one combined Shuna's magic with Mary's magic – Shuna's talent for altering, changing magic.

When you have this element of change, combined with the inherent volatility of Mary's own magic, combined again with the fact that neither of them actually knew how to perform this particular piece of space magic, combined a third time with the realization that only Mary actually seen Tanya use this magic on more than one occasion…

Well, if you were expecting a good result after all of that, you must be either delusional or stupidly optimistic.

Which brings us to the here and now.

"Uh, Shuna! What do we do!"

"We're fine!"

"That's not what I asked!"

"Just- just reel it in!"

"Reel it in?"

"Reel it in, Mary!! Stop adding magicules, and-"

It was all going wrong. Obviously.

Luckily, they had a trump card on hand, just across the clearing.

A trump card that had been jolted from her nap by what was very nearly a magical black hole blaring against her senses.

Don't worry, everyone. Tanya was here to save the day, like always.

"Honestly, what are you two doing?"

The sphere, half as tall as the trees and spinning at a terrifying pace, completely halted in place, as if instantly frozen.

Tanya walked past Mary and Shuna, her arm half extended and palm facing the sky.

"Tanya?" The two echoed, glancing at each other before staring incredulously at the scene in front of them.

"Really, this might be on me. I should have said something like 'an alcove in reality' or 'a locker in reality'." Tanya curled her pointer finger in the universal "come hither" motion. "Calling it a 'hole' might just lead to the creation of magicule-based whirlpools in best case, and reality-breaking magical black holes at worst."

The sphere of frozen space magic drifted towards her, like a dog being beckoned, As it was pulled towards her, she held her hand up, pressing it against the sphere's surface just as it came within her reach.

"Luckily, this isn't too serious a lapse. Closer to the former, really."

She breathed in, holding it a beat before exhaling.

"Break."

Blink, and you would have missed it.

The world around the ball of space magic seemed almost to warp, compressing into nothingness in less than a second. And just like that, the sphere was gone. Utterly. As if it had never been there in the first place.

Tanya turned.

Her hand, the one which had just effortlessly dismantled the piece of combined space magic that had moments before been rampaging on a near out-of-control level, rose to her mouth, covering up a yawn.

"We'll just call it a learning experience for everyone involved."

Mary and Shuna stared.

-=-

Each watched for a time as Tanya approached. There could be no doubt as to the awe in their eyes at what they had just witness-

Ah, no. No, it seems things were quite a bit more heated in Shuna's gaze, as an awe of a different sort took her compared to Mary's completely reasonable and expected amazement.

Perhaps that said something as to Shuna's personality behind closed doors.

Not that that was anyone's business except hers and Tanya's.

Right, moving on then. The long and short of it was this.

Tanya, having felled a Demon Lord Seed and repurposed the Seed itself, now possessed the Unique Skill: Tetra Breaker.

In truth, it performed exactly as its component parts had.

The functions of the Unique Skill: Tetrabattery Limit Enhancement and the Unique Skill: Formulaic Casting had combined into a cohesive unit, providing the same functions at less the hassle.

Formulae could be enhanced directly by the battery of TLE, rather than channeled from one Skill to the other. Furthermore, with only needing to activate one Skill rather than two, the internal requirements – such as focus and mental stamina – decreased.

No matter how natural using her magical abilities – whether they were mana or magicule based – came to her after years of practice, such a change was undoubtedly a great boon.

Indeed, she hardly had to even think to bring her reinforcement and enhancement spells to full force. It was practically as natural as breathing, you might say, the combination of new ease alongside her years of magical experience on the frontlines as a mage.

Though not quite on the level of instinctive or entirely without thought. In truth, Tanya suspected that she little had need to consciously activate the formulae. More than likely, the power of enhancing and reinforcement would rise naturally and effortlessly, when it's need became apparent to her instincts.

Or something like that. She never claimed to be an expert. Just experienced.

By this basis Tanya's already unmatched magical efficiency had technically increased even more, though her circuits remained the same as they were before her battle with Octavius.

Of course, this couldn't be the only upgrade her abilities had received. This was a Demon Lord Seed that had been repurposed, after all. To merely grant the combination of Skills would almost be an insult to those who had bled and died in even the faintest, most futile attempt at grasping such power.

But such a thing was not yet to be.

Though magic itself, whether as magicules or otherwise, very nearly sung in the veins of one Tanya von Degurechaff, the time was not yet at hand. Her influence over magicules, her ability to wield their power, rivaled many that had long since been considered unrivaled.

However, do not be mistaken. Her power could not match these individuals.

Not yet.

If she were to come to blows with the likes of these phenomenal foes, her loss would be the conclusion. But, her efficiency, her potential, her craftiness, and all the other things that made her Tanya… these were to be feared. Now, and as long as she existed.

Yet, above all, there was one trait of the individual known as Tanya that should be feared more than any other. One that made her dangerous beyond compare, regardless of strength.

For within Tanya existed a will to survive, strong enough to outlast even Deities.

No, now was not the time. Not until such a time had passed, and the appropriate conditions had been met, would the Ultimate power of the Unique Skill be fully realized.

But, it should be noted by any potential adversaries that Tanya had been granted the Unique Skill: Tetra Breaker.

After all, willpower was a fundamental tool in the use of magic. Intent, just the same.

Funny, how that works.

-=-=-=-

A Couple Days Later

Tanya Mary Household

Tempest, Jura Tempest Federation

Something's wrong.

More accurately, something had been wrong for a while now.

With Tanya.

That it had gotten bad enough for Mary to notice meant it was a serious problem.

For example…

-=-

Mary was relaxing in her room, polishing the blade so the green shined even without magic flowing through it. Sword training that morning had been tiring, as usual, so it was nice to just sit at home and relax for a bit.

Yep, it was a great feeling to just sit in her room enjoying the peace and-

CRASH

Well, these things never last, do they?

Mary's body moved before any thoughts could register. She shot to her feet, then to the open door of her room.

"What happened?" Mary exclaimed, leaning past the frame. Her katana glinted as she held out protectively.

No one was attacking them, was the first thing she realized. The only thing of note was…

Near the kitchenette, Tanya was crouched down, the shattered remains of a pink mug splayed across the tiles.

Huh.

Mary watched for a moment, confused, before stepping back in her room. She grabbed her katana's sheath, sliding the blade in and setting it next to her futon. She was out of the room a second later, making her way quickly to Tanya's side.

"Tanya?" Mary crouched down next to her.

"Oh. Sue." Tanya glanced at her for a second, before resuming her previous actions.

"What happened?"

Tanya's hand halted for the briefest instance, before depositing another piece of mug in her other hand.

"I dropped a mug, in case you somehow couldn't tell. Thankfully it was empty."

Alright, dick. I was just being polite.

"You dropped something?" Mary raised an eyebrow. "If you start being clumsy as well, I worry for our house's stability."

"Mm. My foot caught a loose tile, is all." Tanya stood, the majority of the pieces in hand, "I'll make Rimuru repair it later."

"Rimuru? Why them?" Mary rose as well, following slightly behind as Tanya moved to dump the ceramic pieces in the tall wicker basket they used as a temporary bin.

"They were a general contractor once upon a time." She tilted her hand, the ceramic letting out quiet clinks as they fell against one another on their way down. "That, and I have blackmail. Not that'd I'd need to resort to it, but…"

What blackmail could you possibly have on Rimuru? Actually, I could probably just ask.

"Well, it's always good to have options." Mary allowed.

"I've taught you well."

"By the way, what sort of blackmail are we talking about here?"

"Subtle." Tanya glanced at her, a hint of amusement there, "I can't tell you exactly, but… well, you've seen how absolutely infatuated so many Tempest residents are for Rimuru, yes?"

"Even I'm not that oblivious."

"Well, I happen to know that Rimuru's been intimate with a resident of Tempest, and it isn't Shion, Benimaru, or another of his most open admirers." Tanya shrugged, "So, if I ever want something, all I really have to say is 'Imagine if Shion found out she'll never be the one to take your virginity' and whatever my request is, it becomes granted. Just like that."

"I feel like there's something morally wrong with you blackmailing the leader of this nation we live in."

"Oh definitely. I'm not denying that at all." Tanya said matter-of-factly, "Which is why I've never used it. But you know, I could. And Rimuru knows that."

"Isn't that still technically blackmailing them?"

Tanya said nothing for a moment.

"…No."

You hesitated.

"Well, whatever. As long as you haven't actually…" Mary paused, her brow furrowed, "Wait, how do you know this anyway?"

"Not something you need to worry about."

That's absolutely not going to keep me from worrying about it. Why would Tanya know…

Mary aborted that thought as Tanya moved to crouch down again.

"What are you doing?"

Tanya straightened up, turning and raising an eyebrow at her. "I'm picking up the rest of the mug."

"I mean, I see that. But, why don't you just…"

Mary gestured with a hand, a ball of water appearing in front of it before dropping and washing up the rest of the mug debris. She gestured again, the ball moving to hover over the bin. Then, it vaporized, with the tiny ceramic pieces falling in the bin easily.

Hey, it worked. I couldn't do that a month ago.

"Huh." Tanya said quietly. "Perhaps I forgot."

Mary frowned.

-=-

This, it should be noted, was one instance.

This was not mentioning when Mary witnessed Tanya do the following things within the span of the past couple days:

Running into the doorframe of her room. Running into the doorframe of their house. Nearly dropping the red mug that was meant to replace the pink one that had been dropped in the earlier scene. Napping against a tree during another one of their magic sessions, only to slide off the tree and land on her side next to it… without waking up. Walking out one morning wearing her black boy shorts, an unbuttoned white button up, and nothing else.

Actually, that last one happened fairly often anyway. Mary had seen Tanya's abs almost as much as Shuna at this point.

Not the point.

And these were just the things she could remember off the top of her head!

There was a problem. And since Mary had noticed it, enough that it was obvious, then it was a problem problem.

Which meant something had to be done.

Which meant, naturally, it fell to her.

-=-=-=-

It was fortunate that the opportunity for Mary to do "something" about the situation just so happened to appear that very night.

Light footsteps on the living room tile tipped her off, and just minutes later Mary was dressed and ready.

The front door slid open, then slid shut after a moment 

"The stars nice out tonight?"

Tanya didn't respond.

"That was a joke." Mary stepped outside, making her way over, "You're supposed to laugh."

She sat down next to Tanya, their legs hanging off the raised porch's edge and resting on the snow-covered ground below.

"It's actually pretty cloudy out. I can barely see the moon right now."

Tanya sighed. "What is it, Sue?"

"Well, if we're skipping the small talk..." Mary rolled her eyes, "You should be sleeping right now. What's going on?"

"Nothing is 'going on'. I'm just awake."

"Bullshit."

That got Tanya's attention.

"Excuse me?"

"I said that's bullshit Tanya. And you know it. You think I haven't noticed how much you've been doing lately? You've been working nonstop ever since we got back from Xerxes."

"I'm supposed to be busy. That's my job here. I take care of the little things and the big things, so everything runs smoothly. Not that I'd expect you to understand."

"I'm going to let you have that one." Mary frowned at her, "Fine, Tanya. If you're going to work yourself to exhaustion, fine. Go ahead. If that's your job, then do your job. But you can't do that on top of sleep deprivation. If you're going to work all day, you can't be spending your nights not resting."

"It's not that simple."

"It is that simple."

"No, it isn't." Tanya insisted, still not looking at her.

"Then tell me why it isn't!" Mary burst, grabbing Tanya's shoulder, "For fuck's sake Tanya, this isn't like you at all!"

She resisted the urge to wince. Subtlety and fine emotional control were never going to be Mary's strong suit, it seemed.

"Don't you think I know that?!" Tanya hissed, turning and pushing Mary's hand away. "Do you really think I'm unaware of how unlike me this is? I'm me! And that's the fucking problem, because there shouldn't fucking be a problem at all! I shouldn't have to worry about this, to do everything myself like this. I shouldn't have to wake in the middle of the night in a cold fucking sweat, feeling like that bastard's golden gaze is still locked on my fucking back!!"

Mary's breath caught.

"Golden gaze…?"

Tanya froze.

"Forget it."

"No!" Mary grabbed Tanya's shoulder again, not allowing the other to push her away, "You're right. You're right, Tanya. You shouldn't have to deal with any of this. Not by yourself, not alone. So please, tell me what's going on!"

Tanya clenched her fists. A cool breeze blew across the road, kicking up tiny flurries.

"…Tanya-"

"Sue." Tanya interrupted, "How long would you say Being X was with you?"

"What?" It was like ice down her spine.

Tanya stared down at her clenched hands. "How long were you stuck with Being X?"

"He-" Mary shook her head, repressing a shudder, "That's… not something I want to talk about."

"Neither do I. Humor me."

Mary's grip on Tanya's shoulder tightened.

"…Since Moskov." Her voice was flat. "The first time we ran into each other. Why?"

"Since I came into that world, with the name Tanya." Tanya finally glanced at her, just for a second, "No, before birth, even. That's how long I've known him."

"Since birth…" Mary's eyes widened, her horrified whisper trailing off.

"That cursed computation orb I used, the miracle of science with four cores. It was nothing but a curse, meant to force me into worship against my will. The compulsion to faith filled every pore of my body, even from just seconds of use. The altered deployments, the constant warfare, those were manageable. But I was losing my mind a little more with every near-death bout. If it had gone on much longer, I…"

Tanya huffed. There was no amusement in it.

"Our mutual death was a boon, in that way. Coming too in this world felt like waking up stark sober and hangover-less, after years of having a constant alcoholic buzz. I never wanted to die, but I can admit it likely served me better than staying in a world He controlled."

Silently, Mary agreed with her, still busy processing the information.

Tanya continued.

"Which makes this so irritating. We left him behind. That bastard is gone. He's gone. We're somewhere outside of his control. So why-"

Her voice cracked. She paused, clearing her throat.

"…I've been having… nightmares, I suppose you'd call them. No, I've had them. For a while now. Years, if I'm honest. But they were always sporadic. Not worth thinking about. Until... here. They've just gotten worse. Especially after Xerxes, they're just- I can't escape them anymore. I can't ignore them."

Tanya shook her head.

"There are ones that repeat. Places I've never been. Pain I've never felt. I'm in a field of white flowers under a starless sky. I'm in a forest that keeps changing. I'm on top of a mountain, or a frozen volcano. And sometimes, every so often, far more often than I should… I see him."

The word was whispered with so much venom, it might as well have poisoned the very air.

"I see that bastard. I'm having nightmares about that bastard. Nightmares, like a child. Nightmares, about a problem that doesn't exist anymore. It's infuriating. I shouldn't be having this issue. It's over, he's gone, so I should have just moved past this already and yet…"

Her magic flared for the briefest moment. The snow around their feet kicked up just the slightest bit.

"...and yet, I just- I-"

Warm arms wrapped around her.

Tanya froze, tensing up.

"I get it. I understand better than anyone. You know that, right? I know." Mary emphasized this quietly, her head pressing against Tanya's shoulder, her own shoulders shaking silently.

"And when I say I get it, I really do. I mean, for the longest time… well, I'm sure I woke up yelling enough that you already know. And I think…"

The hug tightened. The tension ebbed out, just a bit.

"…War never really ended for you, did it?"

Something gave way inside.

Wetness trailed down Tanya's face, a few drops falling from her chin. Tanya reached a hand up, touching her own cheek.

I'm… crying?

"Oh." She said quietly. Her hand came back down, resting against Mary's forearm and holding on with a loose grip. "Oh."

"You're the only person I have left from back then. You're the most important person I have. You know that, right?"

Mary's voice was quiet.

"The war is over. He's gone. We're free now. We're free… so you can't treat this like it's just you versus him. Even if it sucks, even if you feel like this is something you should be over and done with already, you- that's just- that'll just get you killed. You're not allowed to do that. You're not allowed to just die. Not like everyone else. Not after we got away. Not after we won."

Tanya sighed after a moment.

"…I don't know… you might not have realized this Mary, but I am a flawed person."

"I do know that, actually." Mary said quietly, "And not for the reason you think. Everyone is flawed. A life without flaws... that kind of thing only exists in a dream, doesn't it?"

Tanya's grip on her forearm tightened.

"Not mine, it seems. I have… a few more flaws than you might think."

"So what? You have a heart. That's what matters."

Me? A heart? Since when?

Before Tanya could come up with a response, another warmth entirely covered her shoulder. A blanket curled around her side, an arm snaking around her left side and waist.

Mary barely had time to blink before the other end of the blanket went over her shoulders as well, an arm curling around her back and a hand hooking her side.

 "It's the middle of winter." Shuna rest her chin on top of Mary's head, pressing the girl's face further into Tanya's shoulder in the process, "And the middle of the night. If…"

She yawned, her eyes fluttering shut.

"If you two are gonna… sit near the snow, you could… at least be warm." Shuna tightened her double hug, "I swear… taking Lord Rimuru's bad example… hm…"

Tanya pulled the edge of the blanket around, incidentally pressing Shuna, who was inside the blanket, closer against them.

"She fell back asleep." Tanya muttered, not quite smiling but clearly feeling better.

"You don't say." Mary mumbled into Tanya's shoulder, the Kijin half atop her as well making it a fairly easy guess.

And that was the end of it. For now.

For now.

~OPENING: TALE OF TWO NATIONS ARC~

-=-=-=-=-=-

Known Skills List

Tanya:

Common Skill: Thought Communication

Extra Skill: Flames of Babylon

Extra Skill: Magic Sense

Extra Skill: Magic Aura

Extra Skill: Voice of the World Communication

Unique Skill: Tetra Breaker

Mary:

Extra Skill: Magic Sense

Extra Skill: Magic Aura

Extra/Intrinsic Skill: Physical Enhancement

Unique Skill: Ability Severance

-=-=-=-=-=-

Tanya's and Mary's swords as I imagine them.

Art by @tanjaded