[Feanor of the Peredhil]

I traveled long, and never far
From reminders of my great dispair
I could not leave them, deeply scarred
Works I devised, and left them there.

Is it perchance Gandalf?

I traveled long

rather self explanitory

never far
From reminders of my great dispair

His great dispair being Sauron and reminders being everywhere, not in the least the Elven ring that he carried.

I could not leave them

He was obligated to stay and help the free peoples of Middle Earth.

deeply scarred

Duh.

Works I devised

Once again, self explanitory.

and left them there

When he finished his 'job', Gandalf left M.E.

Fea