Castillo is an artist, arts researcher, and teacher. His art is hosting assemblies. His work asks questions at the junctions of arts and queer community health. Since 2020, he has conducted research on assemblies as methodologies, which began with the support of erg: école de recherche graphique (Brussels) and the Belgian National Fund for Scientific Research. He is part of the arts collectives and research groups: Aids, archives, and arts assemblies in Belgium (Brussels, 2022–23), Art brut, bruta tú (Madrid), and Buenos Tiempos, Int. (Brussels). He teaches at MULTI at the Brussels Royal Academy of Fine Arts. At the same academy, with Fefa Vila Núñez (Faculty of Sociology and Political Science, Complutense University of Madrid), he conducts a joint research trajectory that asks questions about transmissions, looked at in their form of negotiations, happening within queer activisms and art labour, as well as in between them, in Brussels and in Madrid, from the 1990s to today. They ask questions at a place and a time when arts institutions and queer communities look at the same events from opposing agendas: the conflictual transmissions of queer knowledges, tools, and methodologies, both within community projects and when teaching. Over the past five years, his arts research has been co-produced with, among other arts centers, La Bellone, BUDA, Kaaitheater, Sint Lucas Antwerpen, and Viernulvier in Belgium; Azala, La Escocesa, La Bassa Mar, Hablarenarte, and MACBA in Spain; and the Athens Museum of Queer Arts in Greece. Presently, his research trajectory is supported by a grant from Fédération Wallonie-Bruxelles. He was born in Castilla-La Mancha and lives in Brussels.