[Slob elements, Mutual gain]

"Say, Karna? What's that?"

The white haired young man known both as 'Launcher' and Karna raised his eyebrow as he looked at his brown-haired Master. "What's what, Master?" He didn't sound completely bewildered, but he knew not what the chubby woman was referring to.

The woman known as Jinako huffed a little as she pushed her glasses up, before pointing straight towards the bodysuit-clad Servant's belly. "That, dummy. That little pocket of pudge you're starting to grow on that normally lean belly of yours! I'm supposed to be the chubby, lazy, useless type! You're not trying to encroach on your master's territory, are you?" Despite her modestly heavy figure, the glasses-wearing woman could be described as anything but lazy with the fervor in her speech... right up until she collapsed against the armrest of the couch she was occupying. "Ah, whatever. As long as you keep defending me and making sure that purple-haired witch doesn't touch me, then I don't need to care..."

As Jinako started to drift off into her lazy little mindscape, Karna started to think about the fact he had just become aware of. His belly, formerly lean, was now starting to bulge out against the tight fabric that clung to his body. Sure, he wasn't anywhere near as heavy as his Master, nor was he unable to do his usual duties, but it was still enough to make him a little perplexed. 

"I don't know what exactly you mean by territory, Master, but that is not my intent. This is just as mystifying to me as it is to you, however. Servants like myself aren't supposed to be able to gain weight, unless..." He started to reply, only for the piggish woman on the couch to cough to draw his attention away. He didn't get to think too before his Master's finger met his forehead.

"Less thinking about why it might be happening, Karna. You're still good, even if you end up as fat as me." Jinako didn't sound quite believable, given her NEET status and how little she truly seemed to care about doing anything. Only a fool would believe in her attempts at cheering them up.

So of course Karna believed her. He wasn't a fool, but he was trusting to an enormous fault. His smile made his Master smile back, the shorter lady reaching forward to grab him on the cheeks and plant a little kiss on his forehead.

"That's the ticket, Launcher! Now, go make us some more food! Giving you a pep talk made me hungry, and I don't want to miss the next show on the TV!" Jinako demanded with a little grin on her face. As greedy and as desire-driven as ever. Just the kind of woman that had started to rub off on Karna in all the worst of ways.

As 'Launcher' nodded and started working on the dish that his Master wanted for a 'pre-dinner snack', he was utterly unaware of the true effects that she was having on him. His inner core, the part that would return to the throne once he was defeated... it was starting to bloat, ever so slightly like his gut had. If he kept on blindly obeying his Master and spoiling her, then his core would experience even bigger changes... much like his body would, after he'd share this batch of pizza rolls with her. The utter corrosion of his being's core was in grave danger, and he was powerless to stop it.

After all, the Servant needed food just as much as his Master did.

---

As time passed by, yet again Jinako had to point out how her Servant was starting to pack on the pounds. Despite the fact that they were eating more and more food, he just didn't notice that his belly was starting to bulge further and further out against his outfit. It wasn't just his belly either at this point. His thighs, his delicate arms, and even his face, it was all starting to bulge outward in quite the unflattering way.

Karna initially refused to acknowledge that anything was particularly wrong with his current state, much like Jinako herself usually would, but therein was the core problem. He was starting to act like her. Not entirely, but there were certain aspects that were rubbing off on him.

Most importantly of all...

"Karnaaaaa... Why can't you hold your farts in anymore...?" The brown-haired girl muttered from her spot on the couch, coughing a little as her enlarged body started to wobble just a little. The unrestrained way both Master and Servant went about in regards to eating had definitely started to show its signs on the former.

Frankly speaking, Jinako was starting to turn into a flabby mess. By this point, she had stopped wearing clothes all together, letting her heavy body flounder around as her underwear tried its best to keep it all restrained. The humidity of the repurposed supply closet the two called their 'home' didn't help at all with her heavier frame, causing her entire body to be covered in a thin layer of permanent sweat. She was at least around 200 pounds at this point, if not a few tens above that. At the rate the two of them were gaining, she wouldn't be staying at that weight for long.

"Sorry, Jinako." The white-haired Servant replied, before a soft 'uurrp' echoed out from his mouth. It wasn't just gas from one end that was leaking from the indian Lancer's body, it was coming out of any possible hole that it could muster. Of course it did, considering the kinds of foods that Karna had been preparing for the two of them.

To call the foods that they had been eating fattening would be a disservice to just how effective they had been. From having just a little bit of pudge on his stomach, now he was quickly approaching the 200 pounds mark, and that wasn't just because of muscle mass. In fact, most of that mass had been eroding away due to inaction ever since Jinako started to overeat to try and avoid thinking about her Servant potentially encroaching on her territory in terms of appeal. All that extra food, adding onto his heavy form.

Not to mention, with the way his bodysuit was made, all the sweat that would build up from the stale and warm air within the supply closet would be entirely contained within that fabric... which meant that it would heat poor Karna up even more so than his Master. This resulted in a drastic lack of motivation to do anything, most importantly making food for the tow of them...

Suddenly, as the two flabby messes almost drifted off to a hungry sleep, the tv that they were both eyeballing turned to another channel. A familiar channel with a familiar purple-headed mastermind giggling at their pitiful states.

"BB here! Wow, you two look like absolute wastes! I bet the two of you couldn't possibly move an inch if somebody managed to cram a few meals into those hungry mouths of yours!" She started to snicker smugly, before a number appeared near the bottom of the screen. "Tell you two what, how about I do all of that hard work like cooking, and you just sit back and enjoy the fruits of my labor. Just dial that number on a phone, and you'll never have to worry about it ever again!"

Not even five seconds later, the sound of a phone dialing started to fill the otherwise quiet supply closet, sealing their fate...

---

Several weeks passed since the pair of Master and Servant turned the reins of their life over to the purple haired menace that had taken over the system they lived within. No longer did they need to worry about making sure they had enough food to last them the day, nor about the need to get up and actually make said food.

No, both of them at this point were reduced to relying on their own base needs. Needs that had previously started to align more closely only a little while ago, now fully shared between the two of them. It would seem that spending all of your time locked within a single room, struggling to think of anything but food to satiate your growing stomach, would end up leaving a great impact on both the body and the soul.

Case in point, Karna. At this point, his core concept had completely eroded by his Master's overwhelming presence and allure. What had once been a proud demigod, ready for combat at a moment's notice, was now comparable to a slab of fat trying to squeeze onto the couch.

Where Karna had just been pushing 200 pounds some weeks back, his weight and the size that came with it had absolutely doubled. This earned him a set of arms that were barely functional, a set of legs that could barely support him for a minute, a belly half the size of the couch he was stuck on, and a cute rounded-out face ready to be pinched and teased by somebody fitter.

Of course, given their strengthened bond and shared interests, Jinako was no slouch in the rapid gain area. She had previously been the bigger one of the two, but Karna had somehow managed to catch up to her. This could be owed to the effect her recklessly slobby attitude had on his being, but at this point, neither of them cared. They were both couch-filling fatties, and they were hungry.

The two mountainous mounds let go of their little controllers, having spent time playing a simple game for brief entertainment. Both of them started to reach for the slices of pizza that had been resting upon their respective tummies... but with their meaty fingers, what would've been a small brush turned into knocking all of the food off their domed bodies, right into the little crevice between their bodies.

The desire-ruled pair took a moment to look towards one another, to try and look down and find the food that they had knocked aside... only for their eyes to lock onto one another. Instead of being ruled by their stomachs, the connection they shared as Master and Servant let them experience a small reprieve.

A small reprieve in the form of their hearts beating loudly and audibly. Their feelings for one another were still intact, perhaps even amplified by their fall. Just looking into their respective eyes made the memories of a thinner time run through their minds... and then the memories of their steady but sustained fall, as they grow progressively more intimate to match their waistlines...

While they continued to stare into each others' eyes, a strong warmth started to radiate through their loins. As their lives together flashed on by, so too did all the more intimate moments. Their cheeks flushing red didn't stop them from silently admiring one another and wishing to be just that little bit closer, to inch their lips close enough to partake in just a smidge more intimacy, like they had in the past.

Unfortunately, they were still ruled by their needs, and their bellies growling broke their little moment of silent-albeit-needy affection. They needed food more than they needed love. Thankfully, BB would be stopping by their next meal very soon, so they just had to wait. 

Wait patiently like the piggish couple they had become.