Thing is, strong empathy and strong psychopathy don't really go together.

As much as Belkar's faking "being a team player" - his empathy is, slowly, growing.
Right, which would pre-clude him from being a psychopath, which would imply that this is impossible. I suppose Rich might say this is all fictional anyhow and to not get too hung-up on modern psychoanalysis of the characters, BUT... if we WERE to get thusly hung-up... then Belkar would not rise to the level of a psychopath.

He is, however, a total sadist.

You could, I suppose (as some have here), say that Belkar's foil is similar to how a psychopath mimics regular people, but I really only think that it's a surface comparison. Interesting to note, but not really the same thing. Belkar is much more blase about his role and doesn't take his self-image all that seriously, which narcissists definitely do, and psychopaths at least have some tendency in that area as well.

My thinking is that Belkar's empathy is more severely repressed than non-present. Frankly, V might have had similar issues.