Thor is the god of Thunder, and one of the great gods. His power is over weather and storms.
He is believed to have been the one to originally concoct the Brewing a Storm spell. He used a version of the spell in order to save the inhabitants of the hamlet of Bruce in southeastern Llewdor from a monster that was ravaging the town, after failing to defeat it in hand-to-hand combat. The people praised him for saving them, and begged to build a temple in his honor. The god said he had no need for more places of worship and said that a simple flag marking the site of the battle would suffice. It became known as the banner of Bruce, or Bruce banner. The banner flew for scores of years until another hulking monster (the only thing known about the monster was that it was green) pillaged the village. The village was destroyed, and the banner was torn beyond repair. There was no time to call for divine intervention. Because Thor wasn't around to save the town that time he was blamed for not coming, and when the town was rebuilt, it was without the banner of Bruce.
It is said that Druids worship the 'great gods' and nature, and with the power of these gods are able to control the weather and storms around the Green Isles. It appears they may be summoning on the power of Thor, one of the great gods.
Behind the scenesEdit
Obviously Bruce banner, and the hulking green monster that destroyed Bruce, as well as Thor are a pun, and joke towards Thor, Bruce Banner and the Incredible Hulk from Marvel Comics.
In romantic druid mythology and other pagan traditions the Oak tree is sometimes seen as the symbol of Thor. The druids live on an island where mostly grows Oak. Their Sacred Treasure is the Sacred Oak, and they are concerned with the power to control weather, and storms on the islands (all of these appear to be inspired by romantic druidic Thor traditions).