science fiction setting. Nick Perumov involves Norse gods, creatures and events in his fantasy novel Godsdoom (1995), as well as in its sequels and prequels. Various characters from Norse mythology inspire the naming and characterization of those in J.K. Rowling's Harry Potter series, for example the werewolf Fenrir Greyback and the Death Eater Thorfinn Rowle. Norse mythology plays heavily into the Everworld series of fantasy by K.A. Applegate, Loki and Hel being perhaps the two most notable Norse characters. Michael Jan Friedman's Vidar trilogy (The Hammer and the Horn, 1985, The Seekers and the Sword, 1985, and The Fortress and the Fire, 1988) presents Norse gods both in Asgard and the contemporary world. The novels Bloodtide (1999) and Bloodsong (200) by children's author Melvin Burgess are loosely based on the Völsunga saga legend. He also wrote a short story about pagan sacrifice in the 2008 short story collection Centuries of Stories. Odin, Loki, and several other Norse mythological figures are major characters in Neil Gaiman's novel American Gods (2001). Gaiman returned to such Nordic inspirations when he wrote Odd and the Frost Giants as a World Book Day publication in 2008. This story is loosely based on the Master-Builder narrative found in the Gylfaginning (Old Norse: The Tricking of Gylfi) section of Snorri Sturluson's Prose Edda. The Sea of Trolls (2004) by Nancy Farmer is heavily influenced by Norse mythology. Also, its sequel The Land of the Silver Apples (2007) is based on Norse mythology. The Thrall's Tale (2006) by Judith Lindbergh is heavily influenced by Norse mythology and is partially told by Thorbjorg the Seeress, an Old Norse priestess of the Vinland Sagas. Runemarks by Joanne Harris (2007) is based on the Norse legends, and creates a post Ragnarok world in which the gods have been scattered and their powers diminished. Greg van Eekhout's debut novel Norse Code, released May 2009, retells the story of Ragnarok set in a quickly-deteriorating Los Angeles. The Halo series novel Contact Harvest takes place on the planet Harvest, which contains many references to Norse mythology. These references include locations named after the BiFrost, Utgard with two of the central A.I. characters being named after Loki and Sif. Many other characters and locations contain references to Norse mythology due to the majority of the colony having Scandinavian ancestry. The Tales from the Wyrd Museum trilogy by Robin Jarvis heavily utilizes Norse mythology as the