One of Spain's premier techno DJs, Oscar Mulero is also an accomplished producer who founded his own label, Warm Up, and occasionally released music on prestigious techno labels including Theory Recordings and Tresor. Based in Madrid, Mulero got into music during the 1980s, initially British goth rock bands such as the Cure, Joy Division, Sisters of Mercy, and Fields of the Nephilim, followed later in the decade by electronic body music (EBM) acts such as Front 242, Nitzer Ebb, and A Split Second. Around the turn of the decade, Mulero established himself as a popular techno DJ in Madrid, first as a resident at the New World club and then, more notably, as a resident at another pioneering Madrid techno club, the Omen. His style at the time was based upon Detroit techno (e.g. Underground Resistance) and the IDM sound of Warp (e.g. Aphex Twin), as well as the German hard trance of Harthouse (e.g. Hardfloor) and the ambient output of Fax +49-69/450464 (e.g. Pete Namlook). In time his style would fall more in line with the productions of Jeff Mills and Surgeon.

In 1996 Mulero performed at the third annual Sónar Music Festival in Barcelona, an honor that firmly established him as one of Spain's premier techno DJs. A mix album, About Discipline and Education, followed in 1998 for the Spanish label So Dens, and so did a lot of international DJ gigs. In 2000, Mulero founded Warm Up and began releasing a series of 12" EPs including Medical Mesh (2000), Learning to Be a Machine (2002), Pro-Files (2004), and 46 (2007). He later founded a subsidiary label, Pole, in 2004 and began releasing additional 12" EPs including The Damage Done (2004), Primary Instincts (2004), and El Silencio Habla (2005). Over the years Mulero also released his productions on a variety of other labels including Tsunami Records (Offshore, 2001; The Damage Done, Pt. 2, 2004), Theory (In Bad Company, 2002; Oblivion/Anaconda, 2002; Anaconda Remixes, 2004), and Tresor (Only Dead Fish Go with the Flow, 2007).

Following a 2009 mix CD for Tresor, Mulero entered the new decade with more 12"s on Warm Up and Pole, as well as Labyrinth and Dynamic Reflection. Double CD Grey Fades to Green arrived in 2011, showcasing his more straightforward techno side on first disc The Grey and more abstract IDM material on second disc The Green. Black Propaganda, a less abstract techno album, followed in 2011. Released in 2013, Biosfera, a vinyl-only full-length on Detroit Underground, focused more on downtempo IDM, closely resembling Arovane and much of the Skam roster. Also in 2013, Mulero started Spherical Coordinates, a side project with Christian Wünsch, and the duo released several techno 12"s on Pole and Token. Mulero's mix CD Unknown Landscapes, Vol. 1 also appeared on Pole in 2013. Mulero released another ambitious full-length, Muscle and Mind, in 2015; the CD pressing of the album contained the Dualistic Concept EP as a bonus disc. ~ Jason Birchmeier, Rovi