This is a story based on the song 'Kokoro' from Kagamine Rin, which is one of my favorite songs in Vocaloid. It was a really touching song that made me cried a little while I was listening to it :'3

Disclaimer: I do NOT own the song 'Kokoro' nor the characters, only the story.

*Tenma's POV*

How does it feel like to be with him? Well, I wouldn't have a chance to know anything about a strong feeling called emotion, which was held inside a person's body.

Why am I here? Its because I'm a robot that was built by a lonely, navy blue-haired scientist. He always spent time with me during the day and testing me out with certain parts of my body. He was more cheerful whether I was around him, but for me, the place which normally held a certain organ was completely blank.

Heart. The only program that I never had is a heart.

No matter how many times he tried to add emotions into my system, it always ended up in failure.

"I want to be able to teach you the joy and sadness of a person." The scientist, which I think his name was Tsurugi, softly spoken to me. But all I could do as a reply is a small nod.

With his agony continuing, time was slipping away. He still kept a small smile on his face, even though time is not infinite.

Suddenly, a single tear had formed in the corner of his eyes, slipping down on his pale cheek.

"Why are you crying?" I wanted to know how he felt at that moment, but I just can't. Why? Why can't I share those feelings with him? Why couldn't I have the program 'Heart' when I was first built from his hands?

But it was too late. He already passed away without me noticing. I just couldn't feel any emotion that was held inside me by the time I saw him lying on the ground, lifelessly. How does it feel like when a person that's important to you suddenly passed away, especially there were a lot of questions that left unanswered?

If there's a wish that could ever be granted, all I want is a heart.

I quickly accessed the files from my creator that left before he passed away.

"There it was!'"

Right now, mixed emotions rises up into my newly formed heart. Happiness, sadness, loneliness, disappointment, any emotion that you could've imagined immediately gone stuck into my head.

"So that's how it feels like to be happy and sad..." I touched the place where it held my heart, when a steam of light flashed upon my mind.

In my memory, he told me there were things to be happy about and grieve about.

For hundreds of years after he passed away, I finally understood what he meant at that moment.

The first miracle was that I was born, the second miracle was the time I spent with him, but where's the third miracle?

"Wait!" 'Receiving... message...!... The transmission source...is the future...me?!'

It was totally breathtaking, I never could have thought in my entire life for how much he cared for me, which was an emotionless robot in the first place.

As a thank-you gift, I dedicated all the songs that I sang to Tsurugi, my beloved scientist.

How I wished he could hear them in heaven, he must be happy that I finally learnt what it feels like to be happy or sad.

Crank! Ka-chunk!

"Wait, what...?" It seems like there's a short in my system and could no longer sing.

But of course, I did not feel guilty. I had spent almost my entire life with Tsurugi and vice versa. He was the one who built me when he's alone and I'm glad I got to fullfill my creator's wish before my system went completely shut down.

I touched my upper left body once again, feeling the heartbeat as it went slower and slower. Eventually, I cried for the first time, not because I knew myself was going to die, its becauae I knew how much I missed my creator after he died and finally getting the chance to share my feelings towards him.

"Thank you for bringing me into this world and for the days we spent together."

No words could describe how much I appreciated for everything that he've given me.

I wish I could sing for eternity. Could another wish of mine be granted by one of the Gods?

"Thank you for everything." I closed my eyes, waiting for my heartbeat to stop at any second.

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