Raijin and Fujin were one of the most terrible gods in the Japanese Panteon, both represented in the famous Byoubu (folding screen) panted by Sotatsu Tawaraya in the sixteenth century.
Fujin is the Japanese god of the wind and one of the eldest Shinto gods. He was present at the creation of the world and when he first let the winds out of his bag, they cleared the morning mists and filled the Gate between heaven and earth so the sun shone. Depicted as as a terrifying dark demon wearing a leopard skin, he brings on his shoulder all the winds in a large bag.
Raijin is instead the god of thunder and lightning in Japanese mythology. His name is derived from the Japanese words rai (thunder) and shin (god). He is typically depicted as a demon beating drums to create thunder.
A legend of Chinese Buddhism states that Fujin and Raijin, the god of thunder, were both originally evil demons who opposed Buddha. After a severe battle between the two demons and 33 gods, the demons were captured and converted, working as gods since then, becoming the protectors of the good harvest