Born to a wealthy Chilean family of European descent, Serrano was orphaned as a child and raised by his grandmother. After an education at the Internado Nacional Barros Arana, he developed an interest in writing and far-right politics, allying himself with the Chilean Nazi movement. During the Second World War, in which Chile remained neutral until 1943, Serrano campaigned in support of Nazi Germany and promoted anti-Semitic conspiracy theories through his own fortnightly publication, "La Nueva Edad". In 1942, he joined an occult order founded by a German migrant which combined pro-Nazi sentiment with ceremonial magic and kundalini yoga. It presented the Nazi German leader Adolf Hitler as a spiritual adept who had incarnated to Earth as a savior of the Aryan race and who would lead humanity out of a dark age known as the Kali Yuga. Serrano became convinced that Hitler had not died in 1945 but had secretly survived and was living in Antarctica. After visiting Antarctica, Serrano travelled to Germany and then Switzerland, where he met the novelist Hermann Hesse and psychoanalyst Carl Jung; in 1965, he published a reminiscence of his time with the pair.