Asgard is one of the nine worlds recognized in Norse mythology and is ruled from Valhalla by Odin, the All-Father. It is the home of the Aesir, the main gods of the Norse pantheon, which also include Thor, Baldur, Tyr and Frigg.
In Asgard, Odin and his wife Frigg rule over the Aesir and the Einherjer, the Viking heroes who died in battle. Every day, these heroes leave the giant feast hall of Valhalla to fight, and every evening they are restored to health to feast and drink.
A second group of gods, the Vanir, make their home in the world Vanaheim. These rival gods include Frey and Freja. In later Norse myth, they became a subgroup of the Aesir and were often found in Asgard as well.