Cysteine protease that cleaves specifically after arginine or lysine residues. Does not cleave caspase-specific substrates. Acts as a positive regulator of cell death. Required for both oxidative stress cell death response and hypersensitive cell death response mediated by immune response. Interacts (via N-terminus) with LSD1. Proteolytically processed; by an autocatalytic mechanism. No visible phenotype under normal growth conditions, but suppression of hypersensitive cell death response upon infection with avirulent pathogen. Belongs to the peptidase C14B family.