American settlers continue to spread to the west and took land from Native Americans. As expansion continued, agreements were signed and they were broken with native americans losing their homes and land and force to move west. As Native Americans were forced to more to the west, they are not able to adopt to the environment they are moving to, so they died due to lack of food or diseases.
It protects the innocents from harm
The Answer is Cats because as you said he believed they were used in devils worship.