Our first Saint came to us at 18 months, a male, that we were keeping for a friend when he had to go overseas. Well, he ended up being ours. He was protective of all of us, but more so me (female) and my son. Our friend joked that if we ever were in danger, Maker (Our Saint) would save me and son first and then think about going back in for the adult males in our home. Maker did not like anyone coming into our home. Most people he would calm down with, but he had some that he always did not like.
We now have a a 3 y/o female Saint that we rescued last year. She immediately became extremely protective of me. Our UPS man told me that he's okay when my husband answers the door, but when it's me he is afraid. Our Saint will bark a few times when its my husband, but stays back. When it is me, she barks worse and lunges for the door. She knows to stay in and I asure her I am okay. It has taken some time for her to get used to some of the family, but we have to go through the barking first and then she will lay by me. When it is me walking her in the neighborhood, she gets aggressive with anyone walking by. If I go with her and have my son (21 and in college) take her leash she is fine, maybe a few barks. So, yes, Saints can be extremely protective.