(Kakashi pov)
It's been around a year or so since Yin started living with me, and she has basically been the best thing to the village. She has been helping people in the village when ever they need help. She has helped some of the teams from the academy by training them, though she could be a little nicer. She has convinced me to join the Anbu a month after she came into the Leaf. She also convinced Rin to be a medic for everyone in the village, but I believe the real reason she convinced Rin to do it was because of me. I could tell that they both worry about me, even though Yin doesn't show it. She has been the most caring person to me ever since my dad died.
A few moths ago was my birthday, and my present from Yin was a new ninjutsu she created, which she dubbed the 'lightning disc jutsu'. It basically is putting lightning chakra into a single point, then expand it into the shape of a disc, while also rotating it. It is actually really useful on the field, since it can cut through pretty much anything, even wind jutsu its weakness.
The day after me and Rin asked her when her birthday was, which is now today, but me and Rin were prepared. We asked Minato to help us to, since Yin hangs around Kushina the most when we're all out doing stuff.
'I can't wait to show Yin her present from us,' I thought while going to pick up Yin's present.
(Yin pov)
I was coming bsck home from training another team of genins, since everyone else was busy doing something. Even Kushina was busy doing something, and she usually isn't.
Anyways on my way home I saw Mikoto Uchiha, a beautiful young women with really dark blue hair, one of the only people in the Uchiha clan that actually like me. Not a long story, they just don't like me for some reason.
After talking with her for a few moments, and her saying happy birthday to me, I was on my way home again.
When I got home I opened the door and took off my shoes after I closed it, while saying, "I'm home."
When I turned the lights on, people suddenly jumped up and yelled, "SURPRISE!!"
I was so surprised that I jumped and squealed a bit, though I didn't expect it to sound like a little girl screaming.
When I looked at who surprised me, after I calmed down with taking deep breaths, I saw it was Kakashi, Rin, Minato, and Kushina in our home, with a banner that says 'HAPPY BIRTHDAY YIN'.
"Aww~, you guys actually remembered my birthday," I said touched by what they did, while also surprised they did actually remember when my birthday was, since I didn't try to remind them or anything.
"Of course we remember, why wouldn't we? Plus it's your first birthday in the Leaf Village, we got to celebrate that at least," Kushina said while giving me a big bear hug.
Suddenly, Rin went into another room and came out with a big present.
"We kind of figured that you weren't the kind of person who likes to eat cake, even on your own birthday, so we thought of having Ichiraku after giving you your present," Kushina said while Rin gave me the present.
"Is this from all of you?" I asked looking at all them when no other presents came out.
"Yeah," they all said, answering my question.
"Ok, thanks for the present," I said before unwrapping the present to see it was a long box.
"Now open that box," Kakashi said, when he saw i was confused on what it was. I nodded at him and lifted the top off, and what I saw surprised me saw much my jaw practically hit the floor.
It was a beautiful black katana, where the whole thing was black including the blade. It also had a chain at the end of the hilt that looked like I could wrap it around my arm and swing it. The guard was the word yin in japanese. The actual blade was long and slender at around 49 or so inches, while on the back of it, it had three little edges like if it had claws on the back. The handle was also black, but it was soft and yet sturdy, like it can never go flying out of my hands, no matter what. The sheath was also black, but it said Yami Yin in japanese on it, and it looks like it goes on my back.
It was the most beautiful blade I've ever seen. Yet, it reminds me of a better version of Tensa Zangetsu from Bleach.
"This...this is beautiful, thank you all," I said while getting them all into a big group hug and kissing them all on the forehead. "I love you guys, so much," I said with tears in my eyes.
"We love you too, sis," Kakashi said while hugging me tighter, but I noticed what he said.
"Sis, huh," I teased Kakashi, who gains a somewhat red face.
"Yeah, you just act so sisterly to me, that I can't help but think of you as a sister," Kakashi said surprising everyone present.
"Well, to be honest. I thought of you as a little brother to me, so I guess we're even," I said to Kakashi caringly.
After our moment and calming down, which lasted a little bit since that was kind of emotional, we went back to my new katana.
"What can it do," I asked curious on the blade, since I knew there was something special about it. It came from these four, of course it can do something cool.
"Well, it can actually use your shadow kekkai genkai like a focuser or a lightning rod. It can be infused with your kekkai genkai and can use it to create devastating waves of chakra, that can devastate a mountain, depending on how much chakra you can use," Minato explained, while I was stuck in awe at my blade.
"If used with your shadow cloak (basically lightning cloak like the Raikages, but with shadows from my kekkai genkai; same boosts just more natural for me to use. Figured it out while training with the genins, was experimenting with my shafow kekkai genkai.), it can be a deadly combo against your enemies," Kakashi said, obviously proud in the blade.
"Let me guess: you all pinched in with the design, the materials, and well, everything about it, right?" I asked ('More like stated,') to them, and they all looked proud in what I asked.
"What are you going to name it," Minato asked, which put me into deep thought.
'OK so not Zangetsu, obviously. Not Kage. Not Kuro. Wait that's it,' I thought, until I found the right name.
"Kage no ken," I named the sword, while putting it in its sheath and then putting it on my back.
"Cool name, I like it," Minato said, while Kushina sighs.
"Of course you like it, you would've name it that, but I do actually like the name. It fits you, you know," she said embarrassing Minato, while also making the rest agree on what she said about it suiting me.
"Well, let's go to Ichiraku's for your best birthday dinner ever, you know" she said with stars in her eyes since she loves ramen. Now I see where Naruto got his love for ramen, but Ichiraku is good too. So it makes sense.
After Ichiraku's, everyone went home, including me and Kakashi. On our way home I told Kakashi, "It's okay to call me sis, you know. I don't mind, especially since I'm going to call you 'Lil Bro'," I told Kakashi, who looks embarrassed about it.
"O-okay, s-sis," Kakashi stutters out, which was adorable.
'No, no Yin. You will not become a brocon, no matter how cute Kakashi acts,' I thought to myself (and my partner who I know will keep me straight from that).
"Thanks, lil bro," I told Kakashi, who doesn't look as embarrassed, but still really embarrassed.
That night, I asked my partner on why they were quiet.
'I was quiet, because I knew they were going to throw you a surprise party, but the sword I did not expect,' my partner told me, which actually makes sense.
'OK, your off the hook this time, but next time please talk to me. It was getting kind of lonely when you didn't talk to me," I told my partner, which I am responded by silence. I then bid my partner good night and went to sleep.