Sergio A. Sierra was born in Barcelona in 1975. He combines his passion for writing with his work as a distributor of merchandise and collectible figures. He studied Classical Philology and, for a time, wrote reviews of Asian fantasy cinema and anime for the official magazine of the Scifi channel and in the culture section of free newspapers in the city. In 2007, together with Meritxell Ribas, he published their first illustrated story, "Pincel de Zorro", for the publishing house Ediciones Ondina. In 2009, the Parramon publishing house released his comic book adaptation of Mary Shelley's "Frankenstein", once again in collaboration with Meritxell Ribas. In 2012, he wrote "Pergamino, el hijo del cazador de libros", his first illustrated novel for the Catalan publishing house La Galera. In 2013, this time with the artist Alex Sierra (Las Tierras de Arran and Tierras de Ogon), he published the first volume of "Yôkai – La Conspiración Heike", which was released simultaneously in France and Spain by the publisher 12 Bis. In 2013 and 2014, he adapted several classic children's tales for the Catalan publishing house Vicens Vives. In 2017-2018, he again collaborated with Alex Sierra under the Belgian publisher Sandawe to release the first volume of his comic book album "Hel'blar, Los Cazadores de Draugar" and "Hel'blar, El Rey Bajo El Túmulo". In 2019 and 2020, he advised on the “Mitología Nórdica” book collection for the publisher RBA Coleccionables and wrote two of the novels that make up the collection: "Thor y el Poder de Mjolnir" and "Thor en la tierra de los Gigantes", which have also been published in France, Portugal, and Latin America. In 2025, Sergio A. Sierra will make his debut in the catalog of the Aventuriers d'Ailleurs label with the highly anticipated reissue of his Frankenstein (under the title "Frankenstein or the Modern Prometheus"), which has been unavailable for several years.