Mother Horsefeather, known in earlier life as Sister Horsefeather, was a greedy, avaricious old shryke who served as the Roost-Mother of Undertown during the Twig trilogy. Chubby and squat with scarlet plumage, Mother Horsefeather ran the Bloodoak Tavern.
Mother Horsefeather first appeared during the events of Clash of the Sky Galleons. Not yet elevated to Roost-Mother status, she was known then as "Sister Horsefeather", and she served as Glaviel Glynte's assistant in the Tarry Vine Tavern. When the Leagues of Undertown burned down the Tarry Vine Tavern, she set up a business of her own with the founding of the Bloodoak Tavern.
Like Glaviel Glynte, Mother Horsefeather financed a great many sky pirates and their voyages, including Cloud Wolf's stormchasing voyage, always skimming off some of the profits of the expeditions for herself. At the time Cloud Wolf and Maris abandoned Twig during a ship wreck, they lived in lodgings above the Bloodoak tavern. Cloud Wolf set sail in a sky pirate ship of his own with money lent to him by Mother Horsefeather. When the ship became infested with woodbugs, Cloud Wolf sunk into massive debt.
Mother Horsefeather also commissioned Twig's first sky ship, the Edgedancer, in return for the secret of safe phraxdust production. Mother Horsefeather believed that the secret would allow her to corner the Undertown water market, but Twig thwarted this plan by also spreading the secret all over the city, to Mother Horsefeather's fury.