The aim of this study demonstrates that one decisive and pure altruist (DPA) can change the world if he owns the ability to assimilate others. The research is based on the evolutionary model of Hammond and Axelrod (2006a) which describes the operation of a community in the world. This study shows that we can simulate an decisive pure altruist agent who always performs both in-group and outgroup altruistic behaviors including the dissemination of his altruism and giving of material objects in the interaction and whose agent type of DPA, while ordinary human beings are modeled as four-type agents based on the model of Hammond and Axelrod (2006a) that evolve according to the genetic potential to reproduce. The results show that such an influential pure altruist can make more pure altruists in the community through the dissemination of his altruism and giving of material objects.