MPD, Maybe?

I made a new friend yesterday
His name is Del, not Ash or Shay.
We like a lot of the same things
Like the silence that dawn brings.
He's never heard a songbird, though,
Or seen the pure white of snow.
It seems that we are not the same
Different in all but name.
For secretly I'm Del you see,
Though he's just one more part of me.
A fragment of my soul, perhaps
I think he'll leave when my mind snaps.
But that might take eternity
So enjoy us both; just you, him, and me.

Author's Note

So. The last line is too long for the rest. I don't care. Anything else I've missed?