No, even if they have that rp, there are reasons. There are psychologically reasons of their past which will have lead them to become the person they are. No one is simple a robot out killing without doing anything.
You can kill peopl without talking, that's fine, but you should make up for it by emoting rp. You emote in RL, why shouldn't your char? Want him to have a blank face? Emote it.
Anyone who just says, "My char klills elves" hasn't developped their rp.
With all due respect, you're wrong. Here's why: You are my defeated foe. I have no respect for you or your kind. I've hated your kind since childhood. I hated you enough to kill you. Why would I bother speaking to you?
Just because someone doesn't sit and chat with you, or emote at you as you're suggesting, doesn't mean they aren't RPing. People who've had nonviolent interactions with this character might think he's been RPed incredibly well as a vicious, brutal killer. RP doesn't mean talking, RP doesn't mean emoting. RP means being the character.