[Lord Azagthoth]

What's the profile of an average human...
All attributes 10 and no disads.

So he can kill, murder, maim, as long as no one knows it? People think they have control over their mental disabilities but most often they don't.

The drug user thinks he's not an addict but he becomes more and more of an drug addict each time he uses and still says all out that he isn't an addict.

I would certainly penalize your murderous character with a disad (most likely with a limitation to reflect that he only kills when he thinks he can get away with it).

I have such a character in the group. he claims to be a light side Force user but kills bounded, defenseless prisoners. In a fight kills opponents while not considering other options, etc. He might not like it being penalized, but again, if he wants to play a killing Jedi, he should play a Dark Jedi or Sith (but then he loses his bonuses on healing powers which he doesn't like).

But afterward, if he changes his actions to reflect his character more properly, the penalty can be dismissed after a while.