In the Poetic Edda, Prose Edda, and Heimskringla, Hel is referred to as a daughter of Loki, and to "go to Hel" is to die. In the Prose Edda book Gylfaginning, Hel is described as having been appointed by the god Odin as ruler of a realm of the same name, located in Niflheim. In the same source, her appearance is described as half-black and half-flesh colored, and as further having a gloomy, down-cast appearance. The Prose Edda details that Hel rules over vast mansions, her servants in her underworld realm, and as playing a key role in the attempted resurrection of the god Baldr.