While never has been proven and the favorite horror stories' schtick is a peaceful loving grandma suddenly turning into evil and brutal murderer do have some basis in reality, you cannot discount facial features and gestures as one of the signs of personality. Here is a man who is a demonic possession personified--Kenneth Copeland.
Here is one example from SMO--taken POWs. Immediate begging for life (obviously he will be spared--15 to 20 in Penal Colony). And here is another example of POW. You don't need to know Russian or Ukrainian languages.
Who would you rather trust based on face expressions, speech, intonations, granted the first one is under the stress of being taken POW and believing that Russians will immediately kill him.
