From childhood's hour I have not been
As others were; I have not seen
As others saw; I could not bring
My passions from a common spring.
From the same source I have not taken
My sorrow; I could not awaken
My heart to joy at the same tone;
And all I loved, I loved alone.
Then- in my childhood, in the dawn
Of a most stormy life- was drawn
From every depth of good and ill
The mystery which binds me still:
From the torrent, or the fountain,
From the red cliff of the mountain,
From the sun that round me rolled
In its autumn tint of gold,
From the lightning in the sky
As it passed me flying by,
From the thunder and the storm,
And the cloud that took the form
(When the rest of Heaven was blue)
Of a demon in my view.

There is really one main allusion in Alone. The allusion to heaven and the devil bring about the idea of good and evil. It is suggested that the demon that kept him from seeing the good in life, heaven, was his father who was known to be abusive. This idea that even when everything was going well or should have been it couldn't because of the evil in his life that ruined it all.