Whether Harlan Wade is the main antagonist of the series or not should in my opinion be up to debate. He does not directly cause any harm in the series, nor does he have any evil intent. He did clearly have before as proven by psychic visions in the series but you only see him when he is regretful of his actions during the brief time he is alive in the series.
I believe it would be more accurate to say that the memories of Wade manifested in Alma's mind is the real issue and this only becomes clear in the third installment. It is not clear wether or not she acted as a cause the memories this in the previous games. Clearly she is not a saint. (AMCW)