The security guard at the Woodland Luxury Apartments front desk    apartment building that forms the centre of Fabletown, Grimble is the troll from the tale of the Three Billy Goats Gruff and quite possibly many other tales where a troll features. His possession of an expensive glamour spell despite his relatively lowly job could suggest that, like Bigby, Grimble was refused entry to the Farm facility because of his past history and thus was given the ability to appear human in order to live and work in the city. He has been shown to assume troll form for battle. Even though he is asleep most of the time, supposedly he still knows what is going on. 
 
He's good friends with Boy Blue, Flycatcher (due to their employements at the Woodlands), and Hobbes.