Parkins Gillespie in 'Salem's Lot
Did anyone else expect that Parkins was going to turn out to be the hero of the piece? He is built up as this taciturn but shrewd lawman compared to his hapless deputy who it seems like will know what to do once things go south, but he just... leaves town and lives with his sister. Not saying it is a badly executed character arc or anything, just that it caught me by surprise.