When you cross him, or do not agree...he will not forget, and the attacks will start, maybe small at first, but they will be there. Never let your self-confidence be hurt. Best, if you can, get out before that happens.
Narcissists are experts at demeaning others so they can look good to the world - to the point of total frustration, despair, and exhaustion for their intended target. That is their goal and it makes them feel good because then they know they had the POWER TO HURT!
It is all about power, manipulating and striking back. It is also all about getting attention and sympathy, and claiming someone else is wrong and they are a victim of the wrong. It is a mixed-bag that the normal mind cannot fight or figure out. And, they lie so well and so convincingly that no one can believe YOU. It is a terrible place to be in - in the grips of a narcissist.
If the situation is bad, and you meant your post in a serious manner, best run as far and fast as you can.
No joking in anything I said. I indeed disagreed with this fellow before realizing what his makeup was, and he gave me the death of a thousand cuts. It was a miserable time. He is a Christian missionary. Go figure.