Who is The Doctor

Here's the entire song:

I cross the void beyond the mind
The empty space that circles time
I see where others stumble blind
To seek a truth they never find
Eternal wisdom is my guide
I am the Doctor

Through cosmic waste the TARDIS flies
To taste the secret source of life
A presence science can't deny exists
Within, outside, behind
The latitude of human minds
I am the Doctor

My voyage dissects the course of time
"Who knows?" you say - but are you right?
Who searches deep to find the light
That glows so darkly in the night
Toward that point I guide my flight

As fingers move to end mankind
Metallic teeth begin to grind
With sword of truth I turn to fight
The satanic powers of the night
Is your faith before your mind?
Know me - am I the Doctor?