No problems there, it strikes a nice balance and doesn't go down the road of "this is a vampire sculpt therefore vampire." Half happy, half sad about that so it cancels out
As for names...
Savagery
Curelty
Bloodthirst
Viciousness
Ferocity
Barbarity
No Remorse
Ruthless Warlord
Sadist
Murderous Intent
Cold Blooded
Some synonyms that might spark ideas. I personally like using Sadistic or Sadist in some way or Ruthless because it not only speaks for his personality but the personalities of those around him if he is able to kill your own figures to spark this rise in morale among them.