The year was 20XX... Dr. Albert Wily had been defeated for good by the super fighting robot, Megaman. Howver, with the further advances in robotic technology, Dr. Thomas Light knew that it was only a matter of time before an even greater threat appeared. With Megaman deactivated, and Dr. Light's newest fighting robot- Megaman X years away from being completed, the Earth was in need of a new, unexpected hero...

"Aaaalright Roll, a few more tweaks and we'll be all done with your upgrades" a young man said to Roll, Dr. Light's housekeeping robot who was lying on a table as multiple robotic arms operated on her.

"What kind of upgrades am I in need of? I thought housekeeping robots didnt need these..." Roll responded to the young man, who was typing away commands into a computer.

"You heard what Dr. Light said, Roll. Without Megaman, we need a new robot who can defend us in case of a new threat. And only god know's where protoman's gone off too..." The young man replied calmly, before hitting enter on his keyboard, causing all of the robot arms to stop their work on Roll "There we are! Done with your upgrades!"

"Thanks! Uhh... What was your name..?" Roll asked the young man, rising off of the table and slipping on a pair of basic white panties and a white bra.

"..." The young man fell silent for a bit...

"D. Just... Call me D" He finally replied "Dr. Light's new lab assistant!"

"Well thanks a bunch D! So tell me, what're these upgrades all about?" Roll asked, checking her body out.

Looking down at herself, Roll noticed how much larger her butt appeared after the upgrade, and how it made her old panties seem so small- appearing as if she was wearing a thong, or even no panties at all.

"...And could you also tell me what happened to my ass while you're at it..?" Roll asked curiously.

"No problem! But first, please proceed into the next room Roll." D called out over a speaker, as Roll did as he said and walked into the next room, her practically 20 inch rump getting stuck in the doorway briefly.

The next room was a completely white space, all with a single monitoring room to the side which Roll could see D standing in.

"Ok Roll, in here we'll be testing out your new combat features so we can make sure there aren't any errors with your new body." D continued over a speaker, before inputting something on a keyboard, causing a holographic Sniper Joe to appear before Roll. "Protoman ran on nuclear energy, Megaman ran on solar energy, but we've recently come across a new, all natural fuel that you're currently running on. We're testing you here to see how well it works."

"Sounds neat... So now are you going to explain WHY my butt's so damn big!?" Roll asked D impatiently.

"Well big butts are always handy for rear-end landings..." D began, "...And trust me, when you need to 'exhaust' you're going to thank me for giving you all that storage space.."

"What?" Roll asked confused

"NOTHING."

...

"Anyway lets carry on now!"

Suddenly the Sniper Joe charged at Roll in an attempt to ram her with its shield, but the blonde robot dodged as the fighting robot instinct immediately took over within her, as her arms immediately transformed into a pair of megabusters (or Roll busters, in this case).

"Come and get some Joe!" Roll shouted out, now full of confidence as the two engaged each other with their busters, firing round after round of energy pellets at each other, before long the Sniper Joe had a clear advantage.

"Roll, use charged shots!" D yelled out to Roll, as she slowly began losing control of the battle.

As the Sniper Joe fired more blasts at Roll, the female robot slid out of harms way and charged her two busters, and at the right moment fired twin blasts of energy at the Sniper Joe, the fiend's shield being blown away instantly from the powerful attack.

"Woah..." Roll said to herself as her busters reverted back to being her normal hands, "That... WAS AWESOME!" She cheered, jumping for joy

"Yeah, but Roll-

"Did you see me do that!? I kicked that Joe's butt!"

"No, Roll listen-

"Psshhh, I bet I can take down anything now!"

"Roll, seriously-

"Bring it on world! I can take whatever you got!-

"ROLL TURN AROUND!" D finally managed to get Roll's attention, as she turned around to find the Sniper Joe lived, leaping at Roll to surprise attack her.

Roll screamed as she ran from the Sniper Joe, the confidence she had before completely gone now as the Joe pursued her.

"D! Why aren't my busters coming back!?" Roll panicked, running in circles from the Sniper Joe as he closed in.

"It was the charged shot Roll! You've overheated too much!" D shouted back at Roll

"T-then what do I do!?" Roll replied to D, shaking out of fear in a corner as the Sniper Joe approached slowly.

"What would Megaman do if he overheated? You need to exhaust!"

"My buster's dont have exhaust fans!" Roll whined back to D

Roll turned away from the Sniper Joe as it approached menacingly, cowering like a puppy as her massive derriere pointed at the Joe. Suddenly, her stomach groaned strangely- something only humans usually experience. Could this be a system error?

Suddenly, Roll let out a long, loud fart directly at the Sniper Joe, making the robot revert back to a hologram and disintegrate immediately.

The room filled with silence as Roll got up off of the ground, completely shocked at how powerful her robotic flatulence was.

"I.. I can fart?... Wait, I HAVE AN ANUS!?" She asked herself, massaging her big butt. "What the hell was all that D!?"

"Well for one, it sure seems your systems are working well." D said confidently, "And secondly, yes, you have genitals. Reason being I integrated your new... Flatulence... Capabilities as part of your exhaust mechanic. You should be thanking me! This way you can feel even MORE human!"

"Last I checked, human flatulence doesn't KILL ROBOTS!" Roll snapped back at D.

Suddenly, Roll began emitting a loud beeping noise- a sign she's dangerously overheated.

"Oh, and speaking of exhaust..." Roll began, cancelling the beeping noise as she began steaming and sparking "How am I supposed to exhaust if I dont have any fans?"

"Umm... J-just... Try to flex your butt muscles Roll... And we'll see where that takes us..." D asked of Roll awkwardly..

Slightly confused at this form of exhausting, Roll began to do what D asked of her. Roll barely flexed her butt when almost instantly she released a long, slimy sounding fart causing a large, black stained bulge to form on the back of her white panties. Roll moaned ever so slightly at this sensation of "farting a solid". Is this what human's describe as pleasure? Or better yet is this what the humans described as... Taking a dump..?"

"Aaaahhh~..." Roll sighed, as both she and D noticed the room being filled with a warm, industrial, yet smelly scent. "Yup, I think I just exhausted..."

"Well then, everything seems to be working pretty well Roll! Now get out of here and go clean your ass up" D said to Roll, pinching his nose.

"What!? Why!?" Roll cried out to D, releasing a high pitched fart "I kinda like this new body! And I didnt see anyone asking Rock to clean himself up after exhausting!"

"That's because he exhausted gas." D replied calmly. "And plus Im having way more fun like this." D continued, speaking in a rather perverted manner.

Roll narrowed her eyes in annoyance at not getting her way, before speaking,

"Hey D, you're a lab assistant right? So I assume that makes you in charge of keeping maintenance of the lab and its robots?" Roll asked

"Y-yeah... Why..?" D replied, now slightly worried she may be catching on.

Grunting, Roll pushed even harder from her ass as even more black muck poured out, leading the female robot to squat as her poop filled panties fell from her legs onto the floor. Roll carefully stepped from the smelly mess she left on the floor of the testing room, as the used toilet that was previously her panties was buried under a mound of her poop.

"So I thin YOU should be the one who gets to cleaning." Roll said to D, ending their dispute as her big, bare ass dripped with shit.

Leaving the screening room, D entered the testing room with a mop and rubber gloves, eyeing Roll menacingly.

"Oh, and I do believe I classify as a robot, correct?" Roll taunted D, bending over as her massive buttocks pointed directly at D "So maybe you need to go get some toilet paper too..."

"I'll have you sent to the trash heap for this, Roll..." D said angrily to the defiant robot, who only stared at him wide eyed.

D looked downward to whatever she was staring at, only to see that Roll had noticed his erection at watching her shit herself.

"I can explain"