La obra completa / Mateo Alemán ; Pedro M. Piñero Ramírez y Katharina Niemeyer (directores) (OCLC #897118689)

RDA 6.2.2.10.1 on Complete Works says that such works should get the conventional collective title Works as their preferred title, which in MARC looks like:

240 10 ǂa Works

The Title Proper (associated with the particular manifestation) is also recorded:

245 13 ǂa La obra completa / ...