Enables chromatin DNA binding activity; damaged DNA binding activity; and histone H3-methyl-lysine-9 demethylase activity. Acts upstream of or within cellular response to DNA damage stimulus; histone H3-K9 demethylation; and negative regulation of histone H3-K9 trimethylation. Located in nucleus; pericentric heterochromatin; and site of double-strand break. Orthologous to several human genes including KDM4D (lysine demethylase 4D). [provided by Alliance of Genome Resources, Apr 2022]