I prefer not to see any monsters in KC:D, except man.Remember: homo homini lupus.
But I can imagine a questline where you have to investigate reports of a monster, with mutiple possible sources:
a) a slightly more aggressive individual of the native predator species like wolves or bears (possibly rabid)
b) made up by a person (or a group) to further egoistic goals
c) simple superstition.
And you might solve them in different ways:
a) kill the animal
b) uncover the conspiracy
c) talk sense into people
and last but not least: d) kill various animals and stitch together their bodies or parts of them, to create proof of you slaying a monster.