Stronmaus is the eldest son of Annam; his mother is a sky goddess whose name varies from tale to tale. He is the god of the sun, sky, weather, and joy, with power similar to his power but more good-natured and sunny in temperment.
With Annam ensconced in his Hidden Realm in the Outlands, Stronmaus is the default head of the Giant Pantheon. His realm in the Beastlands (or Ysgard, according to some) is called Stormhold; it is a spectacular cloud palace crafted from gold, platinum, gems, and marble. An enchanted opal pool within it, of apparently endless size, can heal any creature.
Sources: Complete Divine, Defenders of the Faith, Giantcraft,
http://www.wizards.com/rpga/downloads/LG_Deities.zip, Monster Mythology, On Hallowed Ground, Warriors of Heaven