Transcription factor involved in regulation of gene cluster that mediates the biosynthesis of oosporein, a metabolite required for fungal virulence that acts by evading host immunity to facilitate fungal multiplication in insects (PubMed:26305932). Binds oosporein cluster genes at a conserved 5'-CGGA-3' motif with the exception of OpS5 (PubMed:26305932). The presence of this motif in the OpS3 promoter would suggest the formation of a positive feedback loop for self-activation (PubMed:26305932). With the exception of OpS5, disables the expression of other genes associated with oosporein biosynthesis (PubMed:26305932).