Guillermo Varas was a contributor to the Chilean comic books published by Editorial Zig Zag and Quimantú in the 1960s and 1970s. For the war magazine Guerra, he illustrated stories of 'Corresponsales de Guerra' and alternated with Julio Berríos on the series 'C.O.N.U.' (scripts by Juan Bley Monroy). He was also present in Delito with episodes of the series 'Suspenso', written by Ventura Marín, and in Jungla with 'Mawa'. He was one of the early cover illustrators of the 'El Siniestro Dr Mortis' comic, and contributed to Asteroide in the 1980s. In later years, he began to work for foreign publishers.