Mark 5.2: And when Jesus had stepped out of the boat, immediately there met him out of the tombs a man with an unclean spirit. (ESV)
Mark and Luke tell us that when Jesus got out of the boat a man who had a demon met him. This man is the one who made the approach. Matthew’s gospel records that it was two demon possessed men involved in this encounter.
I believe that the demon possessed man that Mark, and Luke following Mark’s account, write about was the dominant character of these two men. Perhaps he was much more violent and the leader of the two, and the one who wanted to be with Jesus afterwards, and the one who ultimately was the most obedient to Jesus by telling others of what Jesus had done for him.
I believe that this man was the one who received the attention of Mark’s and Luke’s gospel accounts because through his example the whole story could be told all the way to the end. I can not prove my interpretation, but I do not think that Matthew’s account of two demoniacs should be dismissed or explained away. It seems reasonable to me that Mark organized his account around one principle character and Luke followed Mark’s account.
From my vantage point I know that I can be wrong. But I am unwilling to say that an editor of Matthew’s gospel put a second demoniac in the narrative because of a faulty memory or a misunderstanding.