Alejo Alejo ( 1635 – 1660 ) was a Chilean mestizo , who fought in the Arauco War . He was the son of the Mapuche cacique Curivilú and the Spanish Isabel de Vivar y Castro who was captured during a Mapuche raid . Isabel and Alejo were rescued five years later and rejoined the Spanish society . Alejo enlisted the Spanish army , but the system of casta s prevented his promotion . As a result , he deserted from the Spanish army and joined the Mapuches , being appointed toqui . Instructed in Spanish military strategy , he posed a serious threat to his former masters , but he died in a crime of passion : after he had sex with a captured Spanish woman his two wives murdered him . Biography . Alejandro Vivar , Isabel ' s father , was a Spanish soldier in the Captaincy General of Chile during the Arauco War against the Mapuches . He led an incursion into Mapuche territory and was ambushed by them . Isabel was captured and engaged to the cacique Curivilú . She had a son with him , known as " Alejandro de Vivar " by the Spanish and " Ñancú " by the Mapuche ; but he used the diminutive form of the name " Alejo " instead . Isabel and Alejo were rescued by the Spanish five years after Isabel ' s capture and returned to Concepción . However , the caste system of the local population meant they were looked down on : Alejo was rejected as a mestizo , and Isabel for having a son with a Mapuche . To avoid the social criticism , Isabel became a nun and lived inside a convent . Alejo was raised by Franciscans and eventually joined the military . Alejo trained as arquebus ier , but he was denied any promotion as he was a mestizo . As a result , he deserted from the Spanish army in 1657 and joined the Mapuche . Alejo returned to the tribe of his father . The Mapuche had a more welcoming attitude towards mestizos than the Spanish , and accepted him . Alejo was valuable to the Mapuches as he had close knowledge of the Spanish military strategy . He informed his father about his life among the Spanish ( known as " huincas " by the Mapuches ) , and expressed his willingness to serve with the Mapuche against them . As the new toqui , Alejo increased espionage activity and intensified the raids of malones to steal cattle , weapons and capture hostages . He introduced the use of incendiary device s to Mapuche warfare , which proved deadly against the city of Concepción . To prevent the complete destruction of the city , the Spanish sent Isabel to parley with him . Alejo agreed to stop the attack because of his love for his mother , but said " " Mother , it will be very difficult for those arrogant " huincas " to look you in the eyes . They are haughty enough to humiliate mestizos , but they are cowards incapable of defending themselves and have to resort to using a woman to parley with the enemy in their name , while they are surely trembling behind those walls " . The other Mapuche were unwilling to stop the attack , but Alejo quickly silenced the objections by splitting open the head of one of the enraged Mapuche with an axe . Alejo continued his march and destroyed the forts of Conuco and Chepe completely . He then massacred the populations of Talcamavida and Santa Juana . He celebrated one of his victories by getting drunk and having sex with a captured Spanish woman . This angered his Mapuche wives who attacked and killed him while he was sleeping , and then escaped to a Spanish fort . The Spanish welcomed them and gave them asylum . In popular media . Víctor Hugo Silva wrote a historical novel about Alejo , " El mestizo Alejo y la Criollita " . The life of Alejo was portrayed in a Chilean historical comic written in 1973 , as part of a number of historical comic books about the history of Chile from the colonization to the " Patria vieja " . The episode " El mestizo Alejo " was published in issues 178 to 184 , with art and scripts by Luis Ruiz Tagle . The actor Diego Ruiz took part in the documentary film " Algo habrán hecho por la historia de Chile " , playing Alejo . The documentary was produced during the Bicentennial of Chile .