Born in Madrid, he began his career in the 1960s with series like Cinco por infinito, published in English by Continuity Comics as Zero Patrol (heavily retouched by editor Neal Adams).
In issue 4 of the same series he drew an outstanding adaptation of the short story "The Drifting Snow" by August Derleth.
Maroto joined Warren Publishing in November 1971 when artists from the Spanish agency Selecciones Ilustradas started appearing in their three horror magazines, Creepy, Eerie and Vampirella.
He also contributed black and white illustrations for the Roger Zelazny book Changeling and Larry Niven's The Magic Goes Away.
Maroto subsequently worked on the series Amethyst, Zatanna, Atlantis Chronicles,[1] The Savage Sword of Conan, Cadillacs and Dinosaurs, Dracula: Vlad the Impaler and X-Men Unlimited.