Frederick is Sylvester's great-uncle and the brother of Quincy. He is romantically involved with the Woman of Mystery, and seems to have an ongoing feud with Amos and Nellie Grubb. He wields a very large axe, possibly as a means of compensating for what he once had (see below).
Frederick was once a skilled wizard before The Crash. However, he did not lose his powers in The Crash, but before it, when he accidentally summoned a powerful and dangerous demon. He managed to magically bind it, losing all of his magical power in the process. In a possible case of Stockholm Syndrome, the demon became romantically involved with Frederick. That demon is the Woman of Mystery.