Who You Are
Understanding who you are means understanding yourself. Knowledge about the self is vital for applying logic to your own existence.
You are when you are happy. You are when you are sad. You are when you feel and what you feel. You are your emotion. You are what you like and what you don't like. You are your ability to comprehend the world around you and draw logical conclusions. You are what you see when you try to imagine something new. And most importantly, you are right now. In essence, you are your soul.
But you are more than that. You are when and where you were born. You are who your parents were. You are where and how you grew up. You are the genetics that you have. You are everyone you once were. And you are everything the universe once was.
You are where you live. You are who your friends are and the people you hate. You are your dreams and you are your nightmares. You are the house you live in, you are the street, the city. You are who you are because every human that is or was, was who they were.
You are a pattern, one that exists in one slice of space-time, one moment you might say, but then immediately stops existing and starts existing in the next slice. Whenever the pattern forms, it is based upon every time it formed before and everything else behind it (directions based on the reversed arrow of time).
When viewed from outside space-time, all these slices, your entire past and future, you appear once again as a pattern. This would be the entire pattern of you, everything you ever were and everything you ever will be.
This then opens up a new question: When is the end of you? The beginning is clear—when you were born. So is death the end? But what about people who were clinically dead yet were revived, or came back to life naturally? They ended momentarily, but then came back. And indeed, when you sleep, not when you dream, there are slices of space-time where you don't exist. So just because someone stops existing doesn't mean they can't come back. Up until the end of space-time, you cannot definitively say someone has ended. And at the end of space-time, nothing can be said anymore. Only from outside space-time could your entire pattern be viewed, and therefore an end be known.
That said, you are heavily dependent on your body, and once it dies, most of the information necessary for you will be lost. Therefore, it is highly unlikely that you will ever come back. Unless you managed to make a copy of your soul, that is.
If you made a copy of your soul but haven't died yet, meaning there are two of you now, which one are you? You are the one you currently are, but both of you have a rightful claim of being you, every you that existed before copying, that is.