After taking a degree in Fine Arts in Pontevedra in 1995, he focussed his artistic activity in painting but also in design band during the last years.
He worked as an advertising creator, landscape designer and audiovisual producer. He also worked as a teacher of Art at García Barros Secondary School in A Estrada.
Regarding painting, he carried out exhibitions all around Galicia and was awarded many prizes and mentions. Together with Anxo Varela and Carmen Martín, he founded the ‘hartismo’ in 2008 by publishing a manifesto that vindicated the search for beauty as the art engine and above all the obsolescence of the term ‘contemporary art’ as opposite to a supposedly classic art. The ‘hartism’ denounced the complicity of museums and public institutions in the acceptance of a paradigm change that was never really assumed by the viewers, which implies an increasing distance from the official culture with people who pay for it. This movement has today hundreds of followers all around the world. In 2011, he founded A Travesa in Santiago de Compostela. A Travesa is a collective studio opened to people that has at the moment nineteen artists from different countries and specialities. The studio opened in September 2011 with a party and a manifesto of the members who showed their intention to use this new studio, not only as a place to change ideas, exhibitions and workshops but also as a way of approaching art to people and free the cultural offer, influenced by the official and institutional art, from mediations and barriers. A Travesa also publishes "Atravesando..." free every three months. The fanzine is edited by Mariano himself that can be also downloaded in the web.
As for design band, his work is also an example of independence and self-management. From 2006 to 2009, he published the three volumes of HISTORIAS DE MARIANO by means of crowdfounding. He also published LA MANCHA NEGRA (2010), A HISTORIA XAMAIS CONTADA XAMAIS CONTADA (2010) and MENSAXES, which was awarded DB Castelao Prize in 2008.
He collaborated in fanzines and independent magazines and worked as a graphic humourist in press. He promoted collective projects of comics and fanzines of all sorts too.
He also publishes digital works, some of which can be downloaded in the web like VACACIONES NA BATEA (2010-2011), a story come out in instalments in his blog.
As for audiovisual, Mariano made a lot of shorts (Sirenas, Mala Herba, Filmiños...), both in flash animation and real image. Some of them are adaptations of his design band works.
He was joint author of the docummentary “CAL VIVA, CAL MORTA, A DERRADEIRA FESTA”, together with Duarte Fernández.
He also collaborated in the film “O Apóstolo”, by Fernando Cortizo, (story board) and in films by Mario Iglesias like “Nais” (poster) and “Catalina” (artistic assistant director and actor).
He worked as a graphic designer for a lot of companies, both as a freelance and in agencies. He made posters for cultural events participating in contests.
In his blog elestudiodemariano.blogspot.com, he shows his projects, audiovisual installations and some digital comics.
All his graphic works can be seen at marianocasas.com They show a narrative and aesthetic style, strongly personal, unique and different like his whole work.