Mason is a neo maybe corso mix he has not had a good life so like neapolitan mastiffs he will choose one owner and bond tightly with them. So that means protective. If you are not familier with these domiant breeds the breed is Not for you. You can not turn the protectiveness off and on like a facuet instead you manage it. He is a sweet boy and he is house trained and is getting better with basic commands. He is super stubborn again breed trait. No kids for him. And looking for a home that knows the breed. 
www.azmastiffrescue.com