My Sister was turned in a Kitsune! - (Brand New Animal, Human!MC)

Despite how insanely ironic things can turn out to be, I have to address the full scope of this situation starting from some background information.

First, my name is Hiwatashi Kagami and I am part of the 'legit' Hiwatashi family as my widowed father ended up marrying a few years after my mother's death. This led me to not only get a step-mother, but also a younger step-sister.

Hiwatashi Nazuna was what you could find when you look in the dictionary for 'social butterfly'.

The orangette was quite the known element in town and I heard of her even before the news of the planned wedding came up. And while I would say that it's been quite recent news for us to become family, we were on good terms. Far from proper brother and sister due to how little we really knew about each other, but still caring towards one another.

It also helped that we were both busy around the time we came to live under the same roof- the girl was going through her last year in high school while I was dealing with the hassle that was uni. We were just a year apart but... well, it felt two different worlds.

I didn't expect this last bit to also become something far greater than I had originally thought it to be.

Still, back to the premise, despite having many admirers, my step-sister had a single long-standing friend that I wound up meeting a few times. And, truth be told, Kagemori Michiru was a good fix to Nazuna's relative lack of friends.

Not only was she the standard tomboy with a golden heart, but she was also the one that pulled Nazuna out of her room to go around and do things rather than read books and watch Netflix all day long after her homework.

Life was slow but nice, nothing to really complain about beyond the frequent 'honeymoon trips' our parents tended to make between their lengthy work trips out of Japan. One day, however, things changed a lot due to something no one could have predicted.

I know that life can be quite surprising at times but... who would have thought I would have been witness to an attempted kidnapping.

I still remember when Michiru asked if I could be around with them as the two girls were going for a late afternoon visit at the park. Michiru's planned training session had been delayed, so she wanted people around to avoid anyone peeping on them or worse.

So, I was just meant to sit by the nearest bench, check on them from time to time and nothing else. I had just lowered my head to look at my phone's screen as I got a message from a classmate about a potential delay to the upcoming geology class when I saw something happen. Various masked individuals suddenly swarmed the duo as they were distracted while talking and walking towards me. They were easily overwhelmed due to the size of these goons, but I was rapidly shifting out of the bench and chasing after the group.

One would think that big and chubby would equate to slower than someone that did some self-defense classes and trained daily, but I actually failed to caught up to them as they got the girls in two different vans. I was outright panicking as I jumped on my scooter and gave chase.

I felt irritated that a decision of two years ago to avoid buying a car to settle for something slimmer and easier to handle almost risked me my step-sister. The vehicle just struggled to keep up with the two vans, but and I almost lost sign of those twice before finding myself taking a difficult decision: the two vans split in two different lanes and then streets, and I knew which of those held my sister and which held Michiru.

With some dismay, I gave chase to the one where I knew Nazuna was being held, and I came to realize this chase was taking us out of Tokyo proper and towards the outskirts. I never went this far out of the big city, but that didn't stop me from keeping up with the van.

We soon arrived to a facility and I had to park somewhere far as... the place looked absolutely scary with towers keeping tracks of anything around its perimeters and I swear I saw some armed people manning those.

What the hell am I looking at?

It looked like one of those US bases that I had heard about, but there were no flags to confirm this. Neither the US flag or the Japanese one. In fact, this looked like some sort of super-secret base that was not aligned to no one. And it made this whole situation odder and scarier.

Part of me wanted to call the police, a sliver of common sense reminding me that my sister's captors were not something that I should be facing on my own but... but really, how the fuck was the police going to deal with that? Hell, I doubted the JSDF would have had much of a chance to break inside without going overkill so... so I had to take this risk on my own.

Before trying to enter the place from some secondary entry, I checked the small fixer bag I had for the scooter. Stuff that I had bought to use in case something happened to my only vehicle, and stuff that could be useful in entering the base without being noticed.

Finding a proper spot to work with took just a minute as I wandered around the perimeter and spotted a section of the metallic net around the base that was covered in bushes. As I snuck through the bushes, I used the heavy duty mini bolt cutter I had retrieved to cut into the net and create a big enough hole to allow me and then Nazuna to pass through.

The first hurdle was thus passed, but the next bit was thinking of a way to get inside the facility without being found by the cameras. There didn't seem to be too many guards around, only random workers. And the solution came in the form of a gated entry to the vents. I had my screwdriver put to work, removing all screws before slipping inside and crawling my way through the facility in an effort to find my step-sister.

This was not how I expected the day to go, not at all, and the soreness of the training session from hours ago still reminding me to not exert myself too much. Five minutes went by in trying to move through the maze-like system of vents, avoiding getting caught by nearby workers and then find where Nazuna was.

Ultimately, I did find her as I reached a small room containing some vat tubes of kind. Numerous of those were already occupied by individuals with... animal features. There were also two individuals talking and chuckling over a specific vat and, while I couldn't see it all since they were covering with their frames, I noticed the hair of the subject and the familiar red hair spot that Nazuna had in her front locks.

Patiently waiting for these to leave, I slowly unscrewed the grated section and then left through it once the two scientists walked away. Looking around, I didn't see any cameras to worry about, and I slowly shifted closer to the bang where Nazuna was and...

W-What did they do to her?

I was shocked by the sight that gone was the simple jovial step-sister of the human kind with long orange hair with a single frontal spot of red locks and... instead I got a pink-haired kitsune with a pink fur of a shade lighter than her hair.

She also appeared slightly curvier, but I stopped myself from ogling her nude frame within the vat and turned my attention to the nearest terminal to deactivate it. It took a few moments for it to drain the water and release the girl out of her containment.

I caught her in my arms, still recoiling by her different appearance.

"N-Nazu?"

My surprised voice was louder than I had planned it to be, and it was enough to stir my sister awake. Slowly but surely, I could see that her eyes were the only thing unchanged, a soft red pair of eyes at that- it was indeed just different.

"...Kagami-nii? W-Where-"

"I'll tell you later. We need to leave," Adrenaline kicked in once more as I heard footsteps approaching. I removed my jacket and put it around her as I pulled her in my arms in a bridal carry and bolted on the opposite direction from where the noises were coming from. "We're not in a safe place."

The girl appeared ot be tense, but she merely nodded as I rushed out through the halls and ignored the loud alarm that was activated. While I was crawling around the base, I had spotted a path to take without getting caught up by any potential guards around. I heard a lot of people shifting left and right, but none managed to stop us as I bolted as rapidly as I could.

It was an intense ten minutes of taking corners for a lengthy safe path to the opening I made on the side of the base. Nazuna was still unconscious as we got out and into the bushes, and I carefully brought her back to the scooter before getting the hell out of there.

Admittedly, it felt odd to feel her hugging against me as I set her to give her front to me while I drove the vehicle, but it was best to avoid her slipping out and falling mid-retreat. Nothing truly bizarre, but it was quite awkward to feel my step-sister's slightly bigger tits against me.

Nothing more happened through the trip back home as none of the captors seemed to have noticed our escape out of the base and had been too busy looking inside to truly check on any escaping vehicles. And that still didn't please my paranoia.

Once we were back home, I carried Nazuna to her bed, left her to rest there and... pretty much zoomed as I checked if there were clues that we may not be in a safe place- that home wasn't safe. All windows were shut and the front door was further secured with three locks and a big heavy box I set against it.

It sounded excessive, but considering what I saw in that facility and what they were doing, I could tell they were going to look for my sister and come in as intensely as possible. The unease ultimately pushed me to not fall asleep as I sat down by the couch in the living room and kept an eye on anything worrisome that could be happening through the night.

I was also worried about Michiru but... I hadn't tracked down where she had been taken, nor I could expect the police to help with that. This entire situation was a mess for a young man with a lot of responsibilities in his life and... I just kept guarding the house through the night while my step-sister slumbered.

A Brand New Day coming forth and bringing out a weirder take on what life had been up to this point. Both for Nazuna and me.

AN

Hiwatashi Kagami didn't expect to have a kitsune step-sister. What he doesn't expect is that this current situation may develop in some interesting situations due to his sister's new instincts and... already-present interests over him.

Michiru shan't be any better in that regard.