Predicted to enable cysteine-type endopeptidase inhibitor activity. Involved in antimicrobial humoral response. Predicted to be located in extracellular region. Predicted to be active in extracellular space. Is expressed in several structures, including gonad; gut; male reproductive gland or organ; and urogenital ridge. Orthologous to several human genes including CST9L (cystatin 9 like). [provided by Alliance of Genome Resources, Apr 2022]