Rashguard design I made for Raven Fightwear, an australian owned fightwear. They provide awesome stuff for mma, bjj, jiu-jitsu and other martial arts activity. And the design, Raijin (雷神?) is a god of lightning, thunder and storms in the Shinto religion and in Japanese mythology. His name is derived from the Japanese words rai (雷?, "thunder") and "god" or "kami" (神 shin?). He is typically depicted as a demon-looking spirit beating drums to create thunder, usually with the symbol tomoe drawn on the drums.
