Lol I did that with my stalker to, it was the 1st time it ever happened but it wasnt the first time I ever took and evil path with a good character, I still cant understand that.
But if u wish to use shadow keeper to change his alignment back then u must go to Affects Tab and then scroll down until u find the one that is titled " Alignment Change" with a variable of 0.... delete it by highlighting it then selecting delete
and then ur alignment will b back to wat it u set it 2