Tyger, tyger, burning bright
(subject of poem, obvious, noticeable)
In the forests of the night
What fearful hand or eye
(what god)
Could frame
(make, create)
Thy fateful
(what happens when large felines get ahold- death)
Symmetry
(beauty, grace, power)

What good god can create beautiful evil in the form of the amazing large felines.
Good vs Evil
Sherlock vs Moriarty
Clark vs Lex
Any tortured Greek hero vs whatever task or monster the teller of the myth wished to use.
In this case, the damaged Patrick vs his Red John.