If there was one major downside to having turned her big brother into her darling baby brother, it was that despite her best efforts Kari couldn't always be there for Tai, even though she knew he needed her. 
There had been a time when he would of had force of will and the courage to stand up for himself but since she had been behind stripping him of that in the process of making him a adorable diaper pooper she took full responsibility over protecting him.
But there was the small issue that she had school and with both their parents working now to help offset the cost of the packs of diapers Tai could go though in a week, he'd been put in a special daycare that was suppose to protect him. 
Suppose to.
So naturally when she dropped by to pick him up after class and found him sobbing in the corner and turned away from her she had been concerned right away. he had been crying for awhile and the most amazing part was he was doing everything he could, to keep Kari from seeing his face.  Still she was the stronger of the two by far these days and had finally gotten a look at his face and gasped in shock. 
smudged on his forehead (showing that a effort to wash it off had been made) LOSER had been written with a black marker and on one cheek 'diaper baby' had been written and on the other 'diaper filler'. 
Outraged but trying not to scare or upset Tai any more she asked him who had done it to him, and Tai looked behind Kari and pointed and then started to sob again, filling his diaper. 
Turning around to to see who was there, Kari narrowed her eyes as she saw Sora in one of the workers uniforms, smirking and waving back, having had a black marker in her hand and slipping it into her apron, and waving bye and heading for the door. 
"M-Miss crabbles already t-talked to her..and she's been f-fired..but she said that ok..she did what she wanted." Tai sobbed.
"..Come on Tai, let's get you home and into the tub, and get those awful things washed off of you. you just forget all about your mean old ex-girlfriend." Kari coo'ed and started to help Tai get ready to go home.
She didn't need him thinking about Sora and getting himself worked up or even trying to figure out a plan of revenge. 
after all..thats what Tai had her for.

Sora had to admit, she would of figured Kari to be the type to come right after her and as such had taken [precautions. She had stayed with Mimi for a week and had Izzy check her room for any sort of a trap before coming back in but everything seemed A OK. 
'heh, maybe Big bad Kari isn't that terrible after all.' Sora thought, heading to the fridge and getting out a bottle of her favorite soda, never noticing the small pin prick in the cork. She also helped herself to a slice of cake in the fridge, coated with frosting which her mother normally despised but Sora just figured it was a welcome back cake. 
It seemed a little odd that the more she drank the soda, the more thirsty she was but Sora just figured it had to do with her nerves, she had been so worked up about what Kari might do, but really..Tai had deserved her revenge and it wasn't even as bad as it could of been! 
She was on her third Soda  and second slice of cake when she realized that had to be way Kari had let bygones be bygones.. Sora hadn't done all that much and anything Kari did could of  brought down the wrong kind of attention and get either Kari or tai put in a nut house somewhere. 
She was in the middle of patting herself on the back for being SO clever when her mom called. 
"hey sweetie, glad your back from your friend Mimi's. I'm gonna need you to head out and pick up some groceries for me. I've already paid for them, they just need to be brought back. Miss okaru's grandson who normally delivers is out sick. I figured you wouldn't mind since there's nothing in the fridge to snack on." her mother said with a laugh. 
"uh..mom what are you talking about, there's cake and pop in the fridge." Sora said, suddenly feeling very..very cold. 
"I think I know whats in my fridge little lady. unless one of your little digifriends popped over to drop off snacks. I think one of them said something about it. that nice girl who looks after her special brother..you know..the boy you used to date." he mom was said.
"O-Oh uh..Mom..I have to go..I need to use the washroom..I'll uh..head out after." Sora said, her tummy starting to cramp. 
"Oh ok. well don't take too long and maybe lay off the sweets. Love you and talk to you later!" her mom said with a cheerful tone and then the line went dead.
Sora dropped the phone and took off for the bathroom in a dead run, her bladder was suddenly ready to burst as were her bowels, but most of all she wanted to trigger her gag reflex and get whatever she had been munching on and drinking down OUT of her system before whatever horrible effects they could have happened. 
the fact she suddenly needed the bathroom so badly gave her a fair idea though as she went from dashing to hobbling, wet farts escaping and she had no doubt that she was staining her formally white panties.
getting to the bathroom door, she found it shut but she could of sworn it had been opened when she'd gotten back..or had she even checked? in any case she tried the handle and naturally, it was locked.
"Sorry, somebodies in here~" Came a voice that Sora had been dreading all week, and her fear combined with her full bladder equaled a drenched pair of yellow shorts and panties and a puddle around her ankles. 
"K-Kari!? Kari please..let me in there! I..I already had a accident!" Sora whimpered, hot tears of shame rolling down her cheeks even as her bladder was already filling up.
"Really now? a big girl like you? tsk, Maybe Tai isn't the only one who needs diapers." Kari said, her voice sounding closer to the door.
"Kari PLEASE! I..I have to take a-" Sora started to say but was cut off.
"A poo poo. you need to make a poo poo in the potty like a big girl. Say it." Kari said, face unseen but Sora had no problem picturing the smug look that had to be etched on the girls face. 
Naturally Sora would of never resorted to such childish terms, she had potty trained early and everything! But desperate times called for desperate measures.
"..Please Kari. I have to poo poo in the potty like a big girl." Sora said, teeth clenched though not just because of her anger, she was in a final countdown till she unloaded in the back of her panties and shorts, and hadn't they already suffered enough!?!
"Hmm nah, I don't think your ready. if you check the linen closet behind you however, you'll find something a little more your level." Kari said then added. "And don't be ashamed to ask for help with them, I've put them on Tai lots~" 
Diapers. it was gonna be fucking diapers. Sora knew it before she even turned to open the closet. 
again she wouldn't of normally even entertained the idea but she was in a losing battle and a dirty diaper would be easier to get rid of, to explain then a pair of smelly panties and shorts. 
it was a package of little stinkers for big girls, a punishment brand she was semi familiar with from when Mimi had been having some nighttime control but she didn't deal to think on that at the moment. 
ripping the package open she put one of the diapers in her mouth, holding it lightly as she tugged her soaked pants and panties off and dropped them in the puddle. 
'at least they can sock up part of it.' Sora thought bitterly. her socks naturally had done some of the work but she didn't have the luxury of getting them off at the moment. 
getting the diaper from between her teeth she unfolded it and tugged it up between her legs and got it taped on just in time, as her bowel finally gave out and she ended up hunching over, farting loudly and filling out the seat of the diaper as the bathroom opened up, and there was Kari with a video camera. 
"Nice, I'm suppose to be making a semi action movie for my video club next week, I think this is totally going in it." Kari said,, keeping the camera on Sora as she yelped and fell to her hands and knees, starting to crawl as much as she could when she had to keep pausing to push more filth into the back of her diaper. 
what had been white and pink with purple butterflies all over it was now a stained dark brown, and drooping big time in the back. 
As Sora paused and went face down butt up and pounded a fist on the floor, getting the last of the mess out in a series of spectacular farts Kari snickered.
"Oh yeah, thats the money shot right there." She said then turned the camera around and held her nose. "You should all be thankful I can't capture the stink little miss farty pants here is making!" 
With everyone out of her system, Sora collapsed on the floor, her head turned to the side and though she was still crying,there was a big dopey smile on her face as a muffled hiss was heard, she was wetting herself. 
Setting the camera aside, Kari made her way over to Sora and knelt down, a hand coming down on the back of the older girls stinky diaper butt. 
"Now, Sora..Do you think you learned your lesson here about picking on Tai, or do I need to go and tie you to the lamp post outside with your poopie diapers on display for you to get the lesson?" Kari asked then added. "Since you didn't do TOO much to him I was willing to keep your punishment mild this time." 
THAT caught Sora's attention and as exhausted as she was, she turned her head to look at Kari with disbelief on her face.
"T-T-This was a MILD punishment!?!" She whimpered out.
"Oh yeah, Like I said, you only wrote on tai and it was your first strike AND well we used to be friends. so all and all dialed back my original plans for you." Kari said cheerfully. 
The mere thought of what could of happened scared Sora so much she started to try and push out anther load into her diapers while her mind did the only thing it could do in such a situation.
it passed out. 

In the aftermath of Kari's little punishment on Sora, the poor girl was never quite the same. Kari had helped her clean up once she'd woken up and even offered to help her get cleaned up and into some panties and pants..but Sora had meekly asked for more diapers. 
She ended up going back to the same daycare where Tai was dropped off every morning but now she's not a worker, she's one of the special boys and girls and she's one of the quietest and most polite kids there, actually meek enough that she gets semi bullied from time to time but Tai protects her. 
He still doesn't like her but well, he just wants to be like his awesome big sister Kari and protect those who can't protect themselves. 
Kinda sweet when you think about it, isn't it?

the end.