One of the failed attempts that preceded the creation of Corric
An Abomination is a Werewolf which has been turned into a vampire. They are very powerful creatures, but the process renders nearly all such victims essentially insane, and they are regarded by both Vampires and Werecreatures as humans regard rabid dogs: things that MUST be destroyed. The only Abomination of recent decades to retain enough sanity to last more than a few months was Corric Lightfoot.