Both this cards don't work properly with Violent: first, i make my Serpentor Paradigm a dragon with Horrific Mutation, but on basic attacks Violent didn't proc even with Flame Dragoleech within 2 spaces. Same happened using Taint on my Skeezick Blackguard, Violent didn't proc even with Serpentor Paradigm within 2 spaces.
It seems that the code for violent only takes the first race into the check, fx if you taint a dragon or arthropod it will gain fury with dragons\ arthros but not with draksars. Not completely sure though
Probably works like this, i can proc Violent with a tainted Vindrax with a Flame dragoleech next to him.