Hilda is a hag who regularly loiters at the Chicago Wizardrail Station. She apparently also invokes the protection of a group called HAGGIS.
She is "an exceedingly ugly old woman wrapped in tattered black robes" whose "eyes had a red tint"; additionally, "her wart-covered nose was the approximate size and shape of a potato." Her breath, surprisingly, smelled "sweet and pleasant," and made Alexandra Quick think of "apple cider and fresh-baked cookies."
In March of 2009, she was reprimanded by a Wizardrail Auror for loitering in the station.
In early January of 2010, she approached Alexandra Quick, offering the girl various ways of bringing the dead back to life before being reprimanded again.
In September of 2010, Quick mistook Gertrude for Hilda in the Goblin Market.