Duke's travels

I am the one who guided you this far,
All you know and all you feel.
Nobody must know my name
For nobody would understand,
And you kill what you fear,
And you fear what you don't understand.

I call you for I must leave,
You're on your own until the end.
There was a choice but now it's gone,
I said you wouldn't understand,
Take what's yours and be damned.