The phrase given at the beginning of the episode, "Awake, arise or be forever fall'n" is from Milton's poem Paradise Lost. They are the first words spoken by Satan to his minions after being kicked out of heaven.
The police record for Billie Trump lists her date of birth as May 1st 1992. This is the real date of birth of the actress who plays her, Madeline Brewer.
The character of Ken Honeycutt (played by Logan Holladay) shares the same surname as a co-producer of 'Grimm', Nancy Honeycutt.
In the prologue the bad guys are driving Cadillacs from the early 1960's.