confused about the ending...

I thought richie was possessed by the devil or was a physical incarnation of satan. It seemed like his only purpose was to sow destruction and mislead all he came into contact with. Right off the bat I sensed that he was a supernatural being when he appeared to be waiting for an invitation into johns home and life. He later confirmed my suspicion when he put so much value on johns invitation into his home. Who's to say that he didn't have a few supernatural tricks up his sleeve, like mind control to a certain extent. At a few points in the film John would get a vacant look and respond to richie with a whispered agreement almost as if he were hypnotized or brainwashed. When richie was telling John that he was a hit man I think he was trying to use that same power. He was attempting to mislead john into killing his wife. He couldn't force him to though, just plant the seed and let John decide for himself. I don't think he was a hit man at all, he was too accurate when he was describing johns innermost thoughts and feelings to know them through any means other than the supernatural. He sensed johns desperate fear, regret and need and targeted him based on those feelings.