I really hate subversion as it has been used as a cudgel in contemporary urban/modern fantasy. I like the rules, and when we start into a point where you slap an old name on your creature because ours are different? Ugh, it's infuriating.

What I like to do is work within the 'rules' set forward by the specific creature, and then try to delve into the why. There's no real deep lore on why they drown their prey, or the reason for later redemption necessarily. Having a little base to build on and then make my own reasons? More fun.