They’re really cool creatures and require an artist to bring them to life, they should have some cool different characteristics like some of them can suicide and blow up!:)
Attachment: Vodyanoi.jpg
Because it’s name sounds silly. 
And Chthonian Gourgers are pretty close.
I fought those in Lionheart: Legacy Of The Crusader. That was a challenging game, but even then those things were just a nuisance.
Not used probably because they’re from a different mythology. Ok, so are the manticores, but at least the whole world knows what a manticore is…