It just hit me who he's talking about in that song. I don't even want to know if I'm right or wrong.
I've misinterpreted lyrics before and been disappointed by the literal definition, but Nine Inch Nail's 'Only' just took on a different meaning for me.
Yes I am alone
Then again I always was
As far back as i can tell
I think maybe it's because
Because you were never really real
To begin with
I just made you up
To hurt myself