Evil really seems to be strictly a societal construct. Humans have evolved sets of what is considered evil over time, and those things change.
But even if there were some general concept of right and wrong, good and evil, moral and immoral, it seems to still depend on the perspective of the person making the distinction.
In a troop of Baboons or Lions, the Alpha Male killing off any infants that are not his progeny does not seem to be considered evil, immoral or wrong, within the construct of baboon or lion societal strictures.
Evil certainly exists, but can it only be determined within the relative collective society?
Evil and wrong and immoral seem to be based on the individuals' and societal perspective.
Aslan is not a
Tame Lion