OK, that was too easy, how about this?
Dan Donaldson
Obviously, the answer to the last one was PI. How about this one:
Over hills and valleys do I wing
Searching for the vilest things
And when I find them, I will stride
To cast the vile things aside.
The irony that you must see
Is that the one who commands me
Is the one that put them there
Now he wants them to disappear.
You say that's too much metaphor
and that your brain is getting sore
Here's one last hint (if not too late)
What am I?