Tharon is the Skandian god of thunder and storms. 

He is mentioned in The Invaders when the Herons want to name the then still unnamed Mangler. Edvin brings up the idea to call it Tharon's Hammer, but his brotherband waves the idea away as being too classical.

Tharon is probably based on Thor, the ancient Nordic god of thunder. Both have a hammer and can cause thunder with it.