I saw a man dressed in black armor in a very vivid vision, which I had while I was meditating. Awake the next day I was browsing the internet, saw him in a psychic chat room, and was drawn to him. But I sense something is wrong, and I am not sure what that might be.
My first thought would be that the man in black armor you saw in your vivid vision was someone you knew in a past lifetime. He could have been a friend or an enemy—if you had an uneasy feeling later, likely it was the latter.
Also wearing black (the color of darkness) armor (perhaps a symbol of violence or warfare) might be another clue that he is not someone whom you want to associate with now.
Another odd thing about this situation is that if he is some acquaintance of yours from a past lifetime, he would probably not be physically recognizable in this present lifetime (souls ordinarily don’t keep the same face/body, etc., from lifetime to lifetime).
In any case, it would be important for now to you to pray to God (and Guru, if you have one) to guide you about what to do (if anything) about this vision and about the person you saw in a psychic chat room.
If you feel uneasy about this situation in any way, then listen to your feelings and do not become further involved. Paramhansa Yogananda often recommended that his followers stay away from psychic phenomena and stick with true and uplifting spiritual teachings and practices offered by the great Masters of yoga, such as he was.
Unless and until you receive further and very clear Divine guidance through prayer and meditation, it is probably best to let this go and give it all back into God’s hands.