Who is Robert Capesterre, also known as Topiltzin from Treasure and what is their importance?

Robert Capesterre, also known as Topiltzin, is a member of a former drug cartel. He was schooled to look and act like a Mexican national, and he is attempting to take over the Mexican government by preaching a mixture of ancient religion and politics. Robert appeals only to the poor masses, and he is planning to win the government by popular acclaim. He is later killed by Dirk Pitt.