The epigram, "You shall break them with a rod," may come from the Bible, Psalm 2, verse 9: "You shall break them with a rod of iron and dash them in pieces like a potter's vessel" (English Standard Version).
When Monroe says that Diana "knows something wicked is this way coming," he's using a reference from Macbeth, the play by William Shakespeare, Act 4, scene 1, in which one of the witches announces the imminent arrival of the title character with the couplet: "By the pricking of my thumbs,/Something wicked this way comes." Ray Bradbury used that second key line for the title of his 1962 novel.
Zerstörer is German for destroyer.
At 8:04 for the first time Diana calls Sean "Dad" rather than "Daddy".
This episode marks the first time Jim Kouf has written an episode of Grimm with his daughter, Brenna Kouf.