I Am A Shadow

I am a shadow.
I used to be his shadow
But now I'm yours.
He's bright,
You're bright too.
I make people seem brighter
Than they actually are.
So to other beings,
You would be the best.
But you wouldn't be
That bright without me.
So where is the appreciation?
I've never heard a thank you.
Why? Because I am just a shadow.
I am just a dark being no one notices.
I am a shadow.