Wikipedia
Jack-In-Irons is a mythical giant of Yorkshire lore who haunts lonely roads. He is covered with chains and wears the heads of his victims. He wields a large, spiked club. His name may not be Jack as other Yorkshire folklore refers to " Jack-of-Green" and more so the name Jack may just be a term for calling the person an unknown male, like John Doe today.
Jack-in-Irons is portrayed in the Merry Gentry series by Laurell K. Hamilton. He is described as about 13 feet tall, with mostly human features but the face (with large tusks) of a boar. His name is Uther.
This Bogie is a terror for travelers. This large giant-like figure is clad in large clanking chains, and supposedly has the severed heads of his enemies tied to his belt. He also wields a large spiked cudgel. He haunts lonely roads in Yorkshire. This is a Solitary Faerie.