The Hour of Death

Plot:

Nick is puzzled by several cases where a suspect who escaped the police is violently dealt with by a masked, cloaked avenger. He even leaves Nick messages, suggesting he is a 'real Grimm' who is cleaning up 'weakling' Nick's messes. But he strikes terror even with gentle Wesen, like the beavers, who seek help through Monroe, who fears it's a descendant of a medieval Grimm vigilante order. Nick suspects a police mole.