Odin is the Allfather, chief of the Æsir and the most complex of the Norse gods [S1][S2][S3]. He is the god of wisdom, war, death, magic (seiðr), poetry, and the runes, and the ruler of the hall Valhalla, where he receives the slain warriors (the Einherjar) in preparation for Ragnarök [S2]. To gain wisdom, he sacrificed one of his eyes to the well-being Mímir [S2]; to win the runes, he hung himself on the world-tree Yggdrasil for nine nights, pierced by his own spear [S1]. His two ravens, Huginn (Thought) and Muninn (Memory), fly over the world each day and report to him; his two wolves, Geri and Freki, and his eight-legged horse Sleipnir are his companions [S2]. Odin is a figure of profound duality: the wise king and the wandering magician, the god of life and the god of death, the allfather and the one who will die to Fenrir at Ragnarök [S1][S2]. He is the patron of the skalds and of the poetic art, and his name is associated with the 'Odinic' trance (the 'Riding Out,' or hamingja) [S3].