Essential excecutor of PIWIL4-piRNA pathway directed transposon DNA methylation and silencing in the male embryonic germ cells (By similarity). Associates with the de novo DNA methylation machinery and repressive chromatin remodeling complexes (By similarity). Tethering of PIWIL4 to a nascent transposable element transcript recruits repressive chromatin remodeling activities and the de novo methylation apparatus through SPOCD1 (By similarity). Not required for piRNA biosynthesis (By similarity). Interacts with DNMT3A, DNMT3C and DNMT3L.