This article is about a subject that is from official sources but is not considered canon.
At one point Mr. Underwood became a hunter, he passed this on to his wife, Julie and his two children, Stewart and Gretchen. It was shown that, for unknown reasons his children liked hum more than Julie. Also, at some unknown point the Underwood family discovered the Sheepsquatch, a monster known for killing dogs, pigs and cattle. Mr. Underwood, Julie and their children battled the Sheepsquatch which ended with the Sheepsquatch killing Mr. Underwood and escaping. This left Julie and her children devastated and seeking vengeance.
Two weeks after his death Julie and her children came in contact with a god known as the Lord of the Hunt and sacrificed to him in order to gain supernatural abilities in order to kill the Sheepsquatch. With the help of fellow hunter Sam and Dean Winchester as well as the powers given to them by the Lord of the Hunt, Gretchen kills the Sheepsquatch who is revealed to be a citizen named Braydon Albright, avenging Mr. Underwood. Julie, upon discovering that Braydon was the Sheepsquatch kicked the head of Braydon's corpse, when asked why she did the action she answered that it was for her dead husband.
- Supernatural: Mythmaker (flashback, mentioned only)
- Mr. Underwood is one of the very few book characters that isn't a law enforcer whose first name is unknown.