Thor is a Norse Thunder God who, unconditionally, makes thunder. He wields the hammer Mjolnir. Thor resides in Asgard, has a brother named Loki, and his father is Odin. He used to be friends with Zaphod Beeblebrox until Zaphod convinced him to be in a rather classless sub-etha video (involving a latex bustier and Damogranian pom-pom squids). In the aftermath, Odin shat a kitten (literally, passing a live tiger cub) and blew up the planet where said video was filmed. As result, Thor is now the 68th most popular deity in the universe, behind Skaoi, god of snowshoes. In And Another Thing..., Thor is approached by Zaphod because Zaphod wants him to kill Bowerick Wowbagger. While doing this, Thor becomes the god of the Nanites (the people of Nano), replacing the controversy about the cheese god. He pretends to kill himself in the process of protecting his followers. Zaphod had arranged it and had become friends once again with Thor. Thor had also knocked out Wowbagger's immortality with the help of Random Dent, who gave him elastic bands to put on his hammer.
Thor, given his divine nature, combat skills and physique, finds Arthur Dent singularly unimpressive, especially when the thunder god is attempting to fascinate Trillian and the Earthman keeps butting in. This ended up in Arthur challenging Thor to a fight, but only to distract him to get Trillian away.